Query execution optimization for partially typed semantics

ABSTRACT

A method includes receiving an initial pipeline including a sequence of commands for execution on a computing system, and obtaining, for each command in the sequence of commands, semantic information. The sequence of commands includes a command with incomplete semantic information. The method further includes generating an abstract semantic tree (AST) with the semantic information and a placeholder for the incomplete semantic information, and manipulating the AST to generate a revised AST. The revised AST corresponds to a revised pipeline that reduces an execution time on the computing system. The method further includes executing the revised pipeline.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/582,519, filed Apr. 28, 2017. Accordingly, this application claimsbenefit under 35 U.S.C. § 120 to U.S. patent application Ser. No.15/582,519. U.S. patent application Ser. No. 15/582,519 is incorporatedherein by reference in its entirety.

BACKGROUND

During operation, computer systems execute instructions. Because of thevolume of instructions used to complete a task and to hide theoperational complexity of the computer system, abstraction is used. Inother words, the abstraction hides the complexity while simultaneouslyallowing various developers and users to create instructions andcommands that are performed on the computer system. Multiple levels ofabstraction may be used. Each level increasingly hides the instructionalcomplexity of the computer system performing the requested operations.For example, end users that interface with applications at the highestlevel of abstraction may not even contemplate how the end user'scommands to the applications are being executed, much less be able tochange the commands to efficiently execute.

BRIEF DESCRIPTION OF DRAWINGS

In the drawings:

FIG. 1 illustrates a networked computer environment in which anembodiment may be implemented;

FIG. 2 illustrates a block diagram of an example data intake and querysystem in which an embodiment may be implemented;

FIG. 3 is a flow diagram that illustrates how indexers process, index,and store data received from forwarders in accordance with the disclosedembodiments;

FIG. 4 is a flow diagram that illustrates how a search head and indexersperform a search query in accordance with the disclosed embodiments;

FIG. 5 illustrates a scenario where a common customer ID is found amonglog data received from three disparate sources in accordance with thedisclosed embodiments;

FIG. 6A illustrates a search screen in accordance with the disclosedembodiments;

FIG. 6B illustrates a data summary dialog that enables a user to selectvarious data sources in accordance with the disclosed embodiments;

FIGS. 7A-7D illustrate a series of user interface screens for an exampledata model-driven report generation interface in accordance with thedisclosed embodiments;

FIG. 8 illustrates an example search query received from a client andexecuted by search peers in accordance with the disclosed embodiments;

FIG. 9A illustrates a key indicators view in accordance with thedisclosed embodiments;

FIG. 9B illustrates an incident review dashboard in accordance with thedisclosed embodiments;

FIG. 9C illustrates a proactive monitoring tree in accordance with thedisclosed embodiments;

FIG. 9D illustrates a user interface screen displaying both log data andperformance data in accordance with the disclosed embodiments;

FIG. 10 illustrates a block diagram of an example cloud-based dataintake and query system in which an embodiment may be implemented;

FIG. 11 illustrates a block diagram of an example data intake and querysystem that performs searches across external data systems in accordancewith the disclosed embodiments;

FIGS. 12-14 illustrate a series of user interface screens for an exampledata model-driven report generation interface in accordance with thedisclosed embodiments;

FIGS. 15-17 illustrate example visualizations generated by a reportingapplication in accordance with the disclosed embodiments;

FIG. 18 illustrates a block diagram of an example pipeline manager inwhich an embodiment may be implemented;

FIG. 19 illustrates a block diagram of an example search head in whichan embodiment may be implemented;

FIG. 20 is a flow diagram that illustrates how a pipeline may beprocessed in accordance with the disclosed embodiments;

FIGS. 21 and 22 are another set of flow diagrams that illustrates how apipeline may be processed in accordance with the disclosed embodiments;and

FIGS. 23A and 23B are examples of processing a search query inaccordance with the disclosed embodiments.

DETAILED DESCRIPTION

Specific embodiments of the invention will now be described in detailwith reference to the accompanying figures. Like elements in the variousfigures are denoted by like reference numerals for consistency.

In the following detailed description of embodiments of the invention,numerous specific details are set forth in order to provide a morethorough understanding of the invention. However, it will be apparent toone of ordinary skill in the art that the invention may be practicedwithout these specific details. In other instances, well-known featureshave not been described in detail to avoid unnecessarily complicatingthe description.

Throughout the application, ordinal numbers (e.g., first, second, third,etc.) may be used as an adjective for an element (i.e., any noun in theapplication). The use of ordinal numbers is not to imply or create anyparticular ordering of the elements nor to limit any element to beingonly a single element unless expressly disclosed, such as by the use ofthe terms “before”, “after”, “single”, and other such terminology.Rather, the use of ordinal numbers is to distinguish between theelements. By way of an example, a first element is distinct from asecond element, and the first element may encompass more than oneelement and succeed (or precede) the second element in an ordering ofelements.

Further, although the description includes a discussion of variousembodiments of the invention, the various disclosed embodiments may becombined in virtually any manner. All combinations are contemplatedherein.

In general, embodiments of the invention are directed to partially typedsemantic optimization. In particular, an initial pipeline is receivedhaving a sequence of commands. One or more embodiments build an abstractsemantic tree (AST) from the initial pipeline using semantic informationabout each command. The semantic information may be complete orincomplete with respect to each command. Complete semantic informationincludes all semantics for the command which incomplete semanticinformation means that at least one piece of semantic information isunknown. For at least one command, the semantic information isincomplete resulting in incomplete information in the AST. Even thoughthe AST has incomplete semantic information, one or more embodimentsmanipulate the AST to create a revised AST that corresponds to a revisedpipeline. The revised pipeline reduces the execution time from theinitial pipeline. Thus, the revised pipeline is executed instead of theinitial pipeline.

Embodiments are described herein according to the following outline:

1.0. General Overview

2.0. Operating Environment

-   -   2.1. Host Devices    -   2.2. Client Devices    -   2.3. Client Device Applications    -   2.4. Data Server System    -   2.5. Data Ingestion        -   2.5.1. Input        -   2.5.2. Parsing        -   2.5.3. Indexing    -   2.6. Query Processing    -   2.7. Field Extraction    -   2.8. Example Search Screen    -   2.9. Data Modelling    -   2.10. Acceleration Techniques        -   2.10.1. Aggregation Technique        -   2.10.2. Keyword Index        -   2.10.3. High Performance Analytics Store        -   2.10.4. Accelerating Report Generation    -   2.11. Security Features    -   2.12. Data Center Monitoring    -   2.13. Cloud-Based System Overview    -   2.14. Searching Externally Archived Data        -   2.14.1. ERP Process Features            3.0 Data Manipulation Pipeline Optimization            4.0 Hardware

1.0. General Overview

Modern data centers and other computing environments can compriseanywhere from a few host computer systems to thousands of systemsconfigured to process data, service requests from remote clients, andperform numerous other computational tasks. During operation, variouscomponents within these computing environments often generatesignificant volumes of machine-generated data. For example, machine datais generated by various components in the information technology (IT)environments, such as servers, sensors, routers, mobile devices,Internet of Things (IoT) devices, etc. Machine-generated data caninclude system logs, network packet data, sensor data, applicationprogram data, error logs, stack traces, system performance data, etc. Ingeneral, machine-generated data can also include performance data,diagnostic information, and many other types of data that can beanalyzed to diagnose performance problems, monitor user interactions,and to derive other insights.

A number of tools are available to analyze machine data, that is,machine-generated data. In order to reduce the size of the potentiallyvast amount of machine data that may be generated, many of these toolstypically pre-process the data based on anticipated data-analysis needs.For example, pre-specified data items may be extracted from the machinedata and stored in a database to facilitate efficient retrieval andanalysis of those data items at search time. However, the rest of themachine data typically is not saved and discarded during pre-processing.As storage capacity becomes progressively cheaper and more plentiful,there are fewer incentives to discard these portions of machine data andmany reasons to retain more of the data.

This plentiful storage capacity is presently making it feasible to storemassive quantities of minimally processed machine data for laterretrieval and analysis. In general, storing minimally processed machinedata and performing analysis operations at search time can providegreater flexibility because it enables an analyst to search all of themachine data, instead of searching only a pre-specified set of dataitems. This may enable an analyst to investigate different aspects ofthe machine data that previously were unavailable for analysis.

However, analyzing and searching massive quantities of machine datapresents a number of challenges. For example, a data center, servers, ornetwork appliances may generate many different types and formats ofmachine data (e.g., system logs, network packet data (e.g., wire data,etc.), sensor data, application program data, error logs, stack traces,system performance data, operating system data, virtualization data,etc.) from thousands of different components, which can collectively bevery time-consuming to analyze. In another example, mobile devices maygenerate large amounts of information relating to data accesses,application performance, operating system performance, networkperformance, etc. There can be millions of mobile devices that reportthese types of information.

These challenges can be addressed by using an event-based data intakeand query system, such as the SPLUNK® ENTERPRISE system developed bySplunk Inc. of San Francisco, Calif. The SPLUNK® ENTERPRISE system isthe leading platform for providing real-time operational intelligencethat enables organizations to collect, index, and searchmachine-generated data from various websites, applications, servers,networks, and mobile devices that power their businesses. The SPLUNK®ENTERPRISE system is particularly useful for analyzing data which iscommonly found in system log files, network data, and other data inputsources. Although many of the techniques described herein are explainedwith reference to a data intake and query system similar to the SPLUNK®ENTERPRISE system, these techniques are also applicable to other typesof data systems.

In the SPLUNK® ENTERPRISE system, machine-generated data are collectedand stored as “events”. An event comprises a portion of themachine-generated data and is associated with a specific point in time.For example, events may be derived from “time series data,” where thetime series data comprises a sequence of data points (e.g., performancemeasurements from a computer system, etc.) that are associated withsuccessive points in time. In general, each event can be associated witha timestamp that is derived from the raw data in the event, determinedthrough interpolation between temporally proximate events having knowntimestamps, or determined based on other configurable rules forassociating timestamps with events, etc.

In some instances, machine data can have a predefined format, where dataitems with specific data formats are stored at predefined locations inthe data. For example, the machine data may include data stored asfields in a database table. In other instances, machine data may nothave a predefined format, that is, the data is not at fixed, predefinedlocations, but the data does have repeatable patterns and is not random.This means that some machine data can comprise various data items ofdifferent data types and that may be stored at different locationswithin the data. For example, when the data source is an operatingsystem log, an event can include one or more lines from the operatingsystem log containing raw data that includes different types ofperformance and diagnostic information associated with a specific pointin time.

Examples of components which may generate machine data from which eventscan be derived include, but are not limited to, web servers, applicationservers, databases, firewalls, routers, operating systems, and softwareapplications that execute on computer systems, mobile devices, sensors,Internet of Things (IoT) devices, etc. The data generated by such datasources can include, for example and without limitation, server logfiles, activity log files, configuration files, messages, network packetdata, performance measurements, sensor measurements, etc.

The SPLUNK® ENTERPRISE system uses flexible schema to specify how toextract information from the event data. A flexible schema may bedeveloped and redefined as needed. Note that a flexible schema may beapplied to event data “on the fly,” when it is needed (e.g., at searchtime, index time, ingestion time, etc.). When the schema is not appliedto event data until search time it may be referred to as a “late-bindingschema.”

During operation, the SPLUNK® ENTERPRISE system starts with raw inputdata (e.g., one or more system logs, streams of network packet data,sensor data, application program data, error logs, stack traces, systemperformance data, etc.). The system divides this raw data into blocks(e.g., buckets of data, each associated with a specific time frame,etc.), and parses the raw data to produce timestamped events. The systemstores the timestamped events in a data store. The system enables usersto run queries against the stored data to, for example, retrieve eventsthat meet criteria specified in a query, such as containing certainkeywords or having specific values in defined fields. As used hereinthroughout, data that is part of an event is referred to as “eventdata”. In this context, the term “field” refers to a location in theevent data containing one or more values for a specific data item. Aswill be described in more detail herein, the fields are defined byextraction rules (e.g., regular expressions) that derive one or morevalues from the portion of raw machine data in each event that has aparticular field specified by an extraction rule. The set of values soproduced are semantically-related (such as IP address), even though theraw machine data in each event may be in different formats (e.g.,semantically-related values may be in different positions in the eventsderived from different sources).

As noted above, the SPLUNK® ENTERPRISE system utilizes a late-bindingschema to event data while performing queries on events. One aspect of alate-binding schema is applying “extraction rules” to event data toextract values for specific fields during search time. Morespecifically, the extraction rules for a field can include one or moreinstructions that specify how to extract a value for the field from theevent data. An extraction rule can generally include any type ofinstruction for extracting values from data in events. In some cases, anextraction rule comprises a regular expression where a sequence ofcharacters form a search pattern, in which case the rule is referred toas a “regex rule.” The system applies the regex rule to the event datato extract values for associated fields in the event data by searchingthe event data for the sequence of characters defined in the regex rule.

In the SPLUNK® ENTERPRISE system, a field extractor may be configured toautomatically generate extraction rules for certain field values in theevents when the events are being created, indexed, or stored, orpossibly at a later time. Alternatively, a user may manually defineextraction rules for fields using a variety of techniques. In contrastto a conventional schema for a database system, a late-binding schema isnot defined at data ingestion time. Instead, the late-binding schema canbe developed on an ongoing basis until the time a query is actuallyexecuted. This means that extraction rules for the fields in a query maybe provided in the query itself, or may be located during execution ofthe query. Hence, as a user learns more about the data in the events,the user can continue to refine the late-binding schema by adding newfields, deleting fields, or modifying the field extraction rules for usethe next time the schema is used by the system. Because the SPLUNK®ENTERPRISE system maintains the underlying raw data and useslate-binding schema for searching the raw data, it enables a user tocontinue investigating and learn valuable insights about the raw data.

In some embodiments, a common field name may be used to reference two ormore fields containing equivalent data items, even though the fields maybe associated with different types of events that possibly havedifferent data formats and different extraction rules. By enabling acommon field name to be used to identify equivalent fields fromdifferent types of events generated by disparate data sources, thesystem facilitates use of a “common information model” (CIM) across thedisparate data sources (further discussed with respect to FIG. 5).

2.0. Operating Environment

FIG. 1 illustrates a networked computer system 100 in which anembodiment may be implemented. Those skilled in the art would understandthat FIG. 1 represents one example of a networked computer system andother embodiments may use different arrangements.

The networked computer system 100 comprises one or more computingdevices. These one or more computing devices comprise any combination ofhardware and software configured to implement the various logicalcomponents described herein. For example, the one or more computingdevices may include one or more memories that store instructions forimplementing the various components described herein, one or morehardware processors configured to execute the instructions stored in theone or more memories, and various data repositories in the one or morememories for storing data structures utilized and manipulated by thevarious components.

In an embodiment, one or more client devices 102 are coupled to one ormore host devices 106 and a data intake and query system 108 via one ormore networks 104. Networks 104 broadly represent one or more LANs,WANs, cellular networks (e.g., LTE, HSPA, 3G, and other cellulartechnologies), and/or networks using any of wired, wireless, terrestrialmicrowave, or satellite links, and may include the public Internet.

2.1. Host Devices

In the illustrated embodiment, a system 100 includes one or more hostdevices 106. Host devices 106 may broadly include any number ofcomputers, virtual machine instances, and/or data centers that areconfigured to host or execute one or more instances of host applications114. In general, a host device 106 may be involved, directly orindirectly, in processing requests received from client devices 102.Each host device 106 may comprise, for example, one or more of a networkdevice, a web server, an application server, a database server, etc. Acollection of host devices 106 may be configured to implement anetwork-based service. For example, a provider of a network-basedservice may configure one or more host devices 106 and host applications114 (e.g., one or more web servers, application servers, databaseservers, etc.) to collectively implement the network-based application.

In general, client devices 102 communicate with one or more hostapplications 114 to exchange information. The communication between aclient device 102 and a host application 114 may, for example, be basedon the Hypertext Transfer Protocol (HTTP) or any other network protocol.Content delivered from the host application 114 to a client device 102may include, for example, HTML documents, media content, etc. Thecommunication between a client device 102 and host application 114 mayinclude sending various requests and receiving data packets. Forexample, in general, a client device 102 or application running on aclient device may initiate communication with a host application 114 bymaking a request for a specific resource (e.g., based on an HTTPrequest), and the application server may respond with the requestedcontent stored in one or more response packets.

In the illustrated embodiment, one or more of host applications 114 maygenerate various types of performance data during operation, includingevent logs, network data, sensor data, and other types ofmachine-generated data. For example, a host application 114 comprising aweb server may generate one or more web server logs in which details ofinteractions between the web server and any number of client devices 102is recorded. As another example, a host device 106 comprising a routermay generate one or more router logs that record information related tonetwork traffic managed by the router. As yet another example, a hostapplication 114 comprising a database server may generate one or morelogs that record information related to requests sent from other hostapplications 114 (e.g., web servers or application servers) for datamanaged by the database server.

2.2. Client Devices

Client devices 102 of FIG. 1 represent any computing device capable ofinteracting with one or more host devices 106 via a network 104.Examples of client devices 102 may include, without limitation, smartphones, tablet computers, handheld computers, wearable devices, laptopcomputers, desktop computers, servers, portable media players, gamingdevices, and so forth. In general, a client device 102 can provideaccess to different content, for instance, content provided by one ormore host devices 106, etc. Each client device 102 may comprise one ormore client applications 110, described in more detail in a separatesection hereinafter.

2.3. Client Device Applications

In an embodiment, each client device 102 may host or execute one or moreclient applications 110 that are capable of interacting with one or morehost devices 106 via one or more networks 104. For instance, a clientapplication 110 may be or comprise a web browser that a user may use tonavigate to one or more websites or other resources provided by one ormore host devices 106. As another example, a client application 110 maycomprise a mobile application or “app.” For example, an operator of anetwork-based service hosted by one or more host devices 106 may makeavailable one or more mobile apps that enable users of client devices102 to access various resources of the network-based service. As yetanother example, client applications 110 may include backgroundprocesses that perform various operations without direct interactionfrom a user. A client application 110 may include a “plug-in” or“extension” to another application, such as a web browser plug-in orextension.

In an embodiment, a client application 110 may include a monitoringcomponent 112. At a high level, the monitoring component 112 comprises asoftware component or other logic that facilitates generatingperformance data related to a client device's operating state, includingmonitoring network traffic sent and received from the client device andcollecting other device and/or application-specific information.Monitoring component 112 may be an integrated component of a clientapplication 110, a plug-in, an extension, or any other type of add-oncomponent. Monitoring component 112 may also be a stand-alone process.

In one embodiment, a monitoring component 112 may be created when aclient application 110 is developed, for example, by an applicationdeveloper using a software development kit (SDK). The SDK may includecustom monitoring code that can be incorporated into the codeimplementing a client application 110. When the code is converted to anexecutable application, the custom code implementing the monitoringfunctionality can become part of the application itself.

In some cases, an SDK or other code for implementing the monitoringfunctionality may be offered by a provider of a data intake and querysystem, such as a system 108. In such cases, the provider of the system108 can implement the custom code so that performance data generated bythe monitoring functionality is sent to the system 108 to facilitateanalysis of the performance data by a developer of the clientapplication or other users.

In an embodiment, the custom monitoring code may be incorporated intothe code of a client application 110 in a number of different ways, suchas the insertion of one or more lines in the client application codethat call or otherwise invoke the monitoring component 112. As such, adeveloper of a client application 110 can add one or more lines of codeinto the client application 110 to trigger the monitoring component 112at desired points during execution of the application. Code thattriggers the monitoring component may be referred to as a monitortrigger. For instance, a monitor trigger may be included at or near thebeginning of the executable code of the client application 110 such thatthe monitoring component 112 is initiated or triggered as theapplication is launched, or included at other points in the code thatcorrespond to various actions of the client application, such as sendinga network request or displaying a particular interface.

In an embodiment, the monitoring component 112 may monitor one or moreaspects of network traffic sent and/or received by a client application110. For example, the monitoring component 112 may be configured tomonitor data packets transmitted to and/or from one or more hostapplications 114. Incoming and/or outgoing data packets can be read orexamined to identify network data contained within the packets, forexample, and other aspects of data packets can be analyzed to determinea number of network performance statistics. Monitoring network trafficmay enable information to be gathered particular to the networkperformance associated with a client application 110 or set ofapplications.

In an embodiment, network performance data refers to any type of datathat indicates information about the network and/or network performance.Network performance data may include, for instance, a URL requested, aconnection type (e.g., HTTP, HTTPS, etc.), a connection start time, aconnection end time, an HTTP status code, request length, responselength, request headers, response headers, connection status (e.g.,completion, response time(s), failure, etc.), and the like. Uponobtaining network performance data indicating performance of thenetwork, the network performance data can be transmitted to a dataintake and query system 108 for analysis.

Upon developing a client application 110 that incorporates a monitoringcomponent 112, the client application 110 can be distributed to clientdevices 102. Applications generally can be distributed to client devices102 in any manner, or they can be pre-loaded. In some cases, theapplication may be distributed to a client device 102 via an applicationmarketplace or other application distribution system. For instance, anapplication marketplace or other application distribution system mightdistribute the application to a client device based on a request fromthe client device to download the application.

Examples of functionality that enables monitoring performance of aclient device are described in U.S. patent application Ser. No.14/524,748, entitled “UTILIZING PACKET HEADERS TO MONITOR NETWORKTRAFFIC IN ASSOCIATION WITH A CLIENT DEVICE”, filed on 27 Oct. 2014, andwhich is hereby incorporated by reference in its entirety for allpurposes.

In an embodiment, the monitoring component 112 may also monitor andcollect performance data related to one or more aspects of theoperational state of a client application 110 and/or client device 102.For example, a monitoring component 112 may be configured to collectdevice performance information by monitoring one or more client deviceoperations, or by making calls to an operating system and/or one or moreother applications executing on a client device 102 for performanceinformation. Device performance information may include, for instance, acurrent wireless signal strength of the device, a current connectiontype and network carrier, current memory performance information, ageographic location of the device, a device orientation, and any otherinformation related to the operational state of the client device.

In an embodiment, the monitoring component 112 may also monitor andcollect other device profile information including, for example, a typeof client device, a manufacturer and model of the device, versions ofvarious software applications installed on the device, and so forth.

In general, a monitoring component 112 may be configured to generateperformance data in response to a monitor trigger in the code of aclient application 110 or other triggering application event, asdescribed above, and to store the performance data in one or more datarecords. Each data record, for example, may include a collection offield-value pairs, each field-value pair storing a particular item ofperformance data in association with a field for the item. For example,a data record generated by a monitoring component 112 may include a“networkLatency” field (not shown in the Figure) in which a value isstored. This field indicates a network latency measurement associatedwith one or more network requests. The data record may include a “state”field to store a value indicating a state of a network connection, andso forth for any number of aspects of collected performance data.

2.4. Data Server System

FIG. 2 depicts a block diagram of an exemplary data intake and querysystem 108, similar to the SPLUNK® ENTERPRISE system. All or a portionof system 108 may be implemented as a computing system. System 108includes one or more forwarders 204 that receive data from a variety ofinput data sources 202, and one or more indexers 206 that process andstore the data in one or more data stores 208. These forwarders andindexers can comprise separate computer systems, or may alternativelycomprise separate processes executing on one or more computer systems.

Each data source 202 broadly represents a distinct source of data thatcan be consumed by a system 108. Examples of a data source 202 include,without limitation, data files, directories of files, data sent over anetwork, event logs, registries, etc.

During operation, the forwarders 204 identify which indexers 206 receivedata collected from a data source 202 and forward the data to theappropriate indexers. Forwarders 204 can also perform operations on thedata before forwarding, including removing extraneous data, detectingtimestamps in the data, parsing data, indexing data, routing data basedon criteria relating to the data being routed, and/or performing otherdata transformations.

In an embodiment, a forwarder 204 may comprise a service accessible toclient devices 102 and host devices 106 via a network 104. For example,one type of forwarder 204 may be capable of consuming vast amounts ofreal-time data from a potentially large number of client devices 102and/or host devices 106. The forwarder 204 may, for example, comprise acomputing device which implements multiple pipelines or “queues” tohandle forwarding of network data to indexers 206. A forwarder 204 mayalso perform many of the functions that are performed by an indexer. Forexample, a forwarder 204 may perform keyword extractions on raw data orparse raw data to create events. A forwarder 204 may generate timestamps for events. Additionally, or alternatively, a forwarder 204 mayperform routing of events to indexers. Data store 208 may contain eventsderived from machine data from a variety of sources all pertaining tothe same component in an IT environment, and this data may be producedby the machine in question or by other components in the IT environment.

2.5. Data Ingestion

FIG. 3 depicts a flow chart illustrating an example data flow performedby Data Intake and Query system 108, in accordance with the disclosedembodiments. The data flow illustrated in FIG. 3 is provided forillustrative purposes only; those skilled in the art would understandthat one or more of the steps of the processes illustrated in FIG. 3 maybe removed or the ordering of the steps may be changed. Furthermore, forthe purposes of illustrating a clear example, one or more particularsystem components are described in the context of performing variousoperations during each of the data flow stages. For example, a forwarderis described as receiving and processing data during an input phase; anindexer is described as parsing and indexing data during parsing andindexing phases; and a search head is described as performing a searchquery during a search phase. However, other system arrangements anddistributions of the processing steps across system components may beused.

2.5.1. Input

At block 302, a forwarder receives data from an input source, such as adata source 202 shown in FIG. 2. A forwarder initially may receive thedata as a raw data stream generated by the input source. For example, aforwarder may receive a data stream from a log file generated by anapplication server, from a stream of network data from a network device,or from any other source of data. In one embodiment, a forwarderreceives the raw data and may segment the data stream into “blocks”, or“buckets,” possibly of a uniform data size, to facilitate subsequentprocessing steps.

At block 304, a forwarder or other system component annotates each blockgenerated from the raw data with one or more metadata fields. Thesemetadata fields may, for example, provide information related to thedata block as a whole and may apply to each event that is subsequentlyderived from the data in the data block. For example, the metadatafields may include separate fields specifying each of a host, a source,and a source type related to the data block. A host field may contain avalue identifying a host name or IP address of a device that generatedthe data. A source field may contain a value identifying a source of thedata, such as a pathname of a file or a protocol and port related toreceived network data. A source type field may contain a valuespecifying a particular source type label for the data. Additionalmetadata fields may also be included during the input phase, such as acharacter encoding of the data, if known, and possibly other values thatprovide information relevant to later processing steps. In anembodiment, a forwarder forwards the annotated data blocks to anothersystem component (typically an indexer) for further processing.

The SPLUNK® ENTERPRISE system allows forwarding of data from one SPLUNK®ENTERPRISE instance to another, or even to a third-party system. SPLUNK®ENTERPRISE system can employ different types of forwarders in aconfiguration.

In an embodiment, a forwarder may contain the essential componentsneeded to forward data. It can gather data from a variety of inputs andforward the data to a SPLUNK® ENTERPRISE server for indexing andsearching. It also can tag metadata (e.g., source, source type, host,etc.).

Additionally, or optionally, in an embodiment, a forwarder has thecapabilities of the aforementioned forwarder as well as additionalcapabilities. The forwarder can parse data before forwarding the data(e.g., associate a time stamp with a portion of data and create anevent, etc.) and can route data based on criteria such as source or typeof event. It can also index data locally while forwarding the data toanother indexer.

2.5.2. Parsing

At block 306, an indexer receives data blocks from a forwarder andparses the data to organize the data into events. In an embodiment, toorganize the data into events, an indexer may determine a source typeassociated with each data block (e.g., by extracting a source type labelfrom the metadata fields associated with the data block, etc.) and referto a source type configuration corresponding to the identified sourcetype. The source type definition may include one or more properties thatindicate to the indexer to automatically determine the boundaries ofevents within the data. In general, these properties may include regularexpression-based rules or delimiter rules where, for example, eventboundaries may be indicated by predefined characters or characterstrings. These predefined characters may include punctuation marks orother special characters including, for example, carriage returns, tabs,spaces, line breaks, etc. If a source type for the data is unknown tothe indexer, an indexer may infer a source type for the data byexamining the structure of the data. Then, it can apply an inferredsource type definition to the data to create the events.

At block 308, the indexer determines a timestamp for each event. Similarto the process for creating events, an indexer may again refer to asource type definition associated with the data to locate one or moreproperties that indicate instructions for determining a timestamp foreach event. The properties may, for example, instruct an indexer toextract a time value from a portion of data in the event, to interpolatetime values based on timestamps associated with temporally proximateevents, to create a timestamp based on a time the event data wasreceived or generated, to use the timestamp of a previous event, or useany other rules for determining timestamps.

At block 310, the indexer associates with each event one or moremetadata fields including a field containing the timestamp (in someembodiments, a timestamp may be included in the metadata fields)determined for the event. These metadata fields may include a number of“default fields” that are associated with all events, and may alsoinclude one more custom fields as defined by a user. Similar to themetadata fields associated with the data blocks at block 304, thedefault metadata fields associated with each event may include a host,source, and source type field including or in addition to a fieldstoring the timestamp.

At block 312, an indexer may optionally apply one or moretransformations to data included in the events created at block 306. Forexample, such transformations can include removing a portion of an event(e.g., a portion used to define event boundaries, extraneous charactersfrom the event, other extraneous text, etc.), masking a portion of anevent (e.g., masking a credit card number), removing redundant portionsof an event, etc. The transformations applied to event data may, forexample, be specified in one or more configuration files and referencedby one or more source type definitions.

2.5.3. Indexing

At blocks 314 and 316, an indexer can optionally generate a keywordindex to facilitate fast keyword searching for event data. To build akeyword index, at block 314, the indexer identifies a set of keywords ineach event. At block 316, the indexer includes the identified keywordsin an index, which associates each stored keyword with referencepointers to events containing that keyword (or to locations withinevents where that keyword is located, other location identifiers, etc.).When an indexer subsequently receives a keyword-based query, the indexercan access the keyword index to quickly identify events containing thekeyword.

In some embodiments, the keyword index may include entries forname-value pairs found in events, where a name-value pair can include apair of keywords connected by a symbol, such as an equals sign or colon.This way, events containing these name-value pairs can be quicklylocated. In some embodiments, fields can automatically be generated forsome or all of the name-value pairs at the time of indexing. Forexample, if the string “dest=10.0.1.2” is found in an event, a fieldnamed “dest” may be created for the event, and assigned a value of“10.0.1.2”.

At block 318, the indexer stores the events with an associated timestampin a data store 208. Timestamps enable a user to search for events basedon a time range. In one embodiment, the stored events are organized into“buckets,” where each bucket stores events associated with a specifictime range based on the timestamps associated with each event. This maynot only improve time-based searching, but also allows for events withrecent timestamps, which may have a higher likelihood of being accessed,to be stored in a faster memory to facilitate faster retrieval. Forexample, buckets containing the most recent events can be stored inflash memory rather than on a hard disk.

Each indexer 206 may be responsible for storing and searching a subsetof the events contained in a corresponding data store 208. Bydistributing events among the indexers and data stores, the indexers cananalyze events for a query in parallel. For example, using map-reducetechniques, each indexer returns partial responses for a subset ofevents to a search head that combines the results to produce an answerfor the query. By storing events in buckets for specific time ranges, anindexer may further optimize data retrieval process by searching bucketscorresponding to time ranges that are relevant to a query.

Moreover, events and buckets can also be replicated across differentindexers and data stores to facilitate high availability and disasterrecovery as described in U.S. patent application Ser. No. 14/266,812,entitled “Site-Based Search Affinity”, filed on 30 Apr. 2014, and inU.S. patent application Ser. No. 14/266,817, entitled “Multi-SiteClustering”, also filed on 30 Apr. 2014, each of which is herebyincorporated by reference in its entirety for all purposes.

2.6. Query Processing

FIG. 4 is a flow diagram that illustrates an exemplary process that asearch head and one or more indexers may perform during a search query.At block 402, a search head receives a search query from a client. Atblock 404, the search head analyzes the search query to determine whatportion(s) of the query can be delegated to indexers and what portionsof the query can be executed locally by the search head. At block 406,the search head distributes the determined portions of the query to theappropriate indexers. In an embodiment, a search head cluster may takethe place of an independent search head where each search head in thesearch head cluster coordinates with peer search heads in the searchhead cluster to schedule jobs, replicate search results, updateconfigurations, fulfill search requests, etc. In an embodiment, thesearch head (or each search head) communicates with a master node (alsoknown as a cluster master, not shown in Fig.) that provides the searchhead with a list of indexers to which the search head can distribute thedetermined portions of the query. The master node maintains a list ofactive indexers and can also designate which indexers may haveresponsibility for responding to queries over certain sets of events. Asearch head may communicate with the master node before the search headdistributes queries to indexers to discover the addresses of activeindexers.

At block 408, the indexers to which the query was distributed, searchdata stores associated with them for events that are responsive to thequery. To determine which events are responsive to the query, theindexer searches for events that match the criteria specified in thequery. These criteria can include matching keywords or specific valuesfor certain fields. The searching operations at block 408 may use thelate-binding schema to extract values for specified fields from eventsat the time the query is processed. In an embodiment, one or more rulesfor extracting field values may be specified as part of a source typedefinition. The indexers may then either send the relevant events backto the search head, or use the events to determine a partial result, andsend the partial result back to the search head.

At block 410, the search head combines the partial results and/or eventsreceived from the indexers to produce a final result for the query. Thisfinal result may comprise different types of data depending on what thequery requested. For example, the results can include a listing ofmatching events returned by the query, or some type of visualization ofthe data from the returned events. In another example, the final resultcan include one or more calculated values derived from the matchingevents.

The results generated by the system 108 can be returned to a clientusing different techniques. For example, one technique streams resultsor relevant events back to a client in real-time as they are identified.Another technique waits to report the results to the client until acomplete set of results (which may include a set of relevant events or aresult based on relevant events) is ready to return to the client. Yetanother technique streams interim results or relevant events back to theclient in real-time until a complete set of results is ready, and thenreturns the complete set of results to the client. In another technique,certain results are stored as “search jobs” and the client may retrievethe results by referring the search jobs.

The search head can also perform various operations to make the searchmore efficient. For example, before the search head begins execution ofa query, the search head can determine a time range for the query and aset of common keywords that all matching events include. The search headmay then use these parameters to query the indexers to obtain a supersetof the eventual results. Then, during a filtering stage, the search headcan perform field-extraction operations on the superset to produce areduced set of search results. This speeds up queries that are performedon a periodic basis.

2.7. Field Extraction

The search head 210 allows users to search and visualize event dataextracted from raw machine data received from homogenous data sources.It also allows users to search and visualize event data extracted fromraw machine data received from heterogeneous data sources. The searchhead 210 includes various mechanisms, which may additionally reside inan indexer 206, for processing a query. Splunk Processing Language(SPL), used in conjunction with the SPLUNK® ENTERPRISE system, can beutilized to make a query. SPL is a pipeline search language in which aset of inputs is operated on by a first command in a command line, andthen a subsequent command following the pipe symbol “I” operates on theresults produced by the first command, and so on for additionalcommands. Other query languages, such as the Structured Query Language(“SQL”), can be used to create a query.

In response to receiving the search query, search head 210 usesextraction rules to extract values for the fields associated with afield or fields in the event data being searched. The search head 210obtains extraction rules that specify how to extract a value for certainfields from an event. Extraction rules can comprise regex rules thatspecify how to extract values for the relevant fields. In addition tospecifying how to extract field values, the extraction rules may alsoinclude instructions for deriving a field value by performing a functionon a character string or value retrieved by the extraction rule. Forexample, a transformation rule may truncate a character string, orconvert the character string into a different data format. In somecases, the query itself can specify one or more extraction rules.

The search head 210 can apply the extraction rules to event data that itreceives from indexers 206. Indexers 206 may apply the extraction rulesto events in an associated data store 208. Extraction rules can beapplied to all the events in a data store, or to a subset of the eventsthat have been filtered based on some criteria (e.g., event time stampvalues, etc.). Extraction rules can be used to extract one or morevalues for a field from events by parsing the event data and examiningthe event data for one or more patterns of characters, numbers,delimiters, etc., that indicate where the field begins and, optionally,ends.

FIG. 5 illustrates an example of raw machine data received fromdisparate data sources. In this example, a user submits an order formerchandise using a vendor's shopping application program 501 running onthe user's system. In this example, the order was not delivered to thevendor's server due to a resource exception at the destination serverthat is detected by the middleware code 502. The user then sends amessage to the customer support 503 to complain about the order failingto complete. The three systems 501, 502, and 503 are disparate systemsthat do not have a common logging format. The order application 501sends log data 504 to the SPLUNK® ENTERPRISE system in one format, themiddleware code 502 sends error log data 505 in a second format, and thesupport server 503 sends log data 506 in a third format.

Using the log data received at one or more indexers 206 from the threesystems the vendor can uniquely obtain an insight into user activity,user experience, and system behavior. The search head 210 allows thevendor's administrator to search the log data from the three systemsthat one or more indexers 206 are responsible for searching, therebyobtaining correlated information, such as the order number andcorresponding customer ID number of the person placing the order. Thesystem also allows the administrator to see a visualization of relatedevents via a user interface. The administrator can query the search head210 for customer ID field value matches across the log data from thethree systems that are stored at the one or more indexers 206. Thecustomer ID field value exists in the data gathered from the threesystems, but the customer ID field value may be located in differentareas of the data given differences in the architecture of thesystems—there is a semantic relationship between the customer ID fieldvalues generated by the three systems. The search head 210 requestsevent data from the one or more indexers 206 to gather relevant eventdata from the three systems. It then applies extraction rules to theevent data in order to extract field values that it can correlate. Thesearch head may apply a different extraction rule to each set of eventsfrom each system when the event data format differs among systems. Inthis example, the user interface can display to the administrator theevent data corresponding to the common customer ID field values 507,508, and 509, thereby providing the administrator with insight into acustomer's experience.

Note that query results can be returned to a client, a search head, orany other system component for further processing. In general, queryresults may include a set of one or more events, a set of one or morevalues obtained from the events, a subset of the values, statisticscalculated based on the values, a report containing the values, or avisualization, such as a graph or chart, generated from the values.

2.8. Example Search Screen

FIG. 6A illustrates an example search screen 600 in accordance with thedisclosed embodiments. Search screen 600 includes a search bar 602 thataccepts user input in the form of a search string. It also includes atime range picker 612 that enables the user to specify a time range forthe search. For “historical searches” the user can select a specifictime range, or alternatively a relative time range, such as “today,”“yesterday” or “last week.” For “real-time searches,” the user canselect the size of a preceding time window to search for real-timeevents. Search screen 600 also initially displays a “data summary”dialog as is illustrated in FIG. 6B that enables the user to selectdifferent sources for the event data, such as by selecting specifichosts and log files.

After the search is executed, the search screen 600 in FIG. 6A candisplay the results through search results tabs 604, wherein searchresults tabs 604 includes: an “events tab” that displays variousinformation about events returned by the search; a “statistics tab” thatdisplays statistics about the search results; and a “visualization tab”that displays various visualizations of the search results. The eventstab illustrated in FIG. 6A displays a timeline graph 605 thatgraphically illustrates the number of events that occurred in one-hourintervals over the selected time range. It also displays an events list608 that enables a user to view the raw data in each of the returnedevents. It additionally displays a fields sidebar 606 that includesstatistics about occurrences of specific fields in the returned events,including “selected fields” that are pre-selected by the user, and“interesting fields” that are automatically selected by the system basedon pre-specified criteria.

2.9. Data Models

A data model is a hierarchically structured search-time mapping ofsemantic knowledge about one or more datasets. It encodes the domainknowledge necessary to build a variety of specialized searches of thosedatasets. Those searches, in turn, can be used to generate reports.

A data model is composed of one or more “objects” (or “data modelobjects”) that define or otherwise correspond to a specific set of data.

Objects in data models can be arranged hierarchically in parent/childrelationships. Each child object represents a subset of the datasetcovered by its parent object. The top-level objects in data models arecollectively referred to as “root objects.”

Child objects have inheritance. Data model objects are defined bycharacteristics that mostly break down into constraints and attributes.Child objects inherit constraints and attributes from their parentobjects and have additional constraints and attributes of their own.Child objects provide a way of filtering events from parent objects.Because a child object always provides an additional constraint inaddition to the constraints it has inherited from its parent object, thedataset it represents is always a subset of the dataset that its parentrepresents.

For example, a first data model object may define a broad set of datapertaining to e-mail activity generally, and another data model objectmay define specific datasets within the broad dataset, such as a subsetof the e-mail data pertaining specifically to e-mails sent. Examples ofdata models can include electronic mail, authentication, databases,intrusion detection, malware, application state, alerts, computeinventory, network sessions, network traffic, performance, audits,updates, vulnerabilities, etc. Data models and their objects can bedesigned by knowledge managers in an organization, and they can enabledownstream users to quickly focus on a specific set of data. Forexample, a user can simply select an “e-mail activity” data model objectto access a dataset relating to e-mails generally (e.g., sent orreceived), or select an “e-mails sent” data model object (or datasub-model object) to access a dataset relating to e-mails sent.

A data model object may be defined by (1) a set of search constraints,and (2) a set of fields. Thus, a data model object can be used toquickly search data to identify a set of events and to identify a set offields to be associated with the set of events. For example, an “e-mailssent” data model object may specify a search for events relating toe-mails that have been sent, and specify a set of fields that areassociated with the events. Thus, a user can retrieve and use the“e-mails sent” data model object to quickly search source data forevents relating to sent e-mails, and may be provided with a listing ofthe set of fields relevant to the events in a user interface screen.

A child of the parent data model may be defined by a search (typically anarrower search) that produces a subset of the events that would beproduced by the parent data model's search. The child's set of fieldscan include a subset of the set of fields of the parent data modeland/or additional fields. Data model objects that reference the subsetscan be arranged in a hierarchical manner, so that child subsets ofevents are proper subsets of their parents. A user iteratively applies amodel development tool (not shown in Fig.) to prepare a query thatdefines a subset of events and assigns an object name to that subset. Achild subset is created by further limiting a query that generated aparent subset. A late-binding schema of field extraction rules isassociated with each object or subset in the data model.

Data definitions in associated schemas can be taken from the commoninformation model (CIM) or can be devised for a particular schema andoptionally added to the CIM. Child objects inherit fields from parentsand can include fields not present in parents. A model developer canselect fewer extraction rules than are available for the sourcesreturned by the query that defines events belonging to a model.Selecting a limited set of extraction rules can be a tool forsimplifying and focusing the data model, while allowing a userflexibility to explore the data subset. Development of a data model isfurther explained in U.S. Pat. Nos. 8,788,525 and 8,788,526, bothentitled “DATA MODEL FOR MACHINE DATA FOR SEMANTIC SEARCH”, both issuedon 22 Jul. 2014, U.S. Pat. No. 8,983,994, entitled “GENERATION OF A DATAMODEL FOR SEARCHING MACHINE DATA”, issued on 17 Mar. 2015, U.S. patentapplication Ser. No. 14/611,232, entitled “GENERATION OF A DATA MODELAPPLIED TO QUERIES”, filed on 31 Jan. 2015, and U.S. patent applicationSer. No. 14/815,884, entitled “GENERATION OF A DATA MODEL APPLIED TOOBJECT QUERIES”, filed on 31 Jul. 2015, each of which is herebyincorporated by reference in its entirety for all purposes. See, also,Knowledge Manager Manual, Build a Data Model, Splunk Enterprise 6.1.3pp. 150-204 (Aug. 25, 2014).

A data model can also include reports. One or more report formats can beassociated with a particular data model and be made available to runagainst the data model. A user can use child objects to design reportswith object datasets that already have extraneous data pre-filtered out.In an embodiment, the data intake and query system 108 provides the userwith the ability to produce reports (e.g., a table, chart,visualization, etc.) without having to enter SPL, SQL, or other querylanguage terms into a search screen. Data models are used as the basisfor the search feature.

Data models may be selected in a report generation interface. The reportgenerator supports drag-and-drop organization of fields to be summarizedin a report. When a model is selected, the fields with availableextraction rules are made available for use in the report. The user mayrefine and/or filter search results to produce more precise reports. Theuser may select some fields for organizing the report and select otherfields for providing detail according to the report organization. Forexample, “region” and “salesperson” are fields used for organizing thereport and sales data can be summarized (subtotaled and totaled) withinthis organization. The report generator allows the user to specify oneor more fields within events and apply statistical analysis on valuesextracted from the specified one or more fields. The report generatormay aggregate search results across sets of events and generatestatistics based on aggregated search results. Building reports usingthe report generation interface is further explained in U.S. patentapplication Ser. No. 14/503,335, entitled “GENERATING REPORTS FROMUNSTRUCTURED DATA”, filed on 30 Sep. 2014, and which is herebyincorporated by reference in its entirety for all purposes, and in PivotManual, Splunk Enterprise 6.1.3 (Aug. 4, 2014). Data visualizations alsocan be generated in a variety of formats, by reference to the datamodel. Reports, data visualizations, and data model objects can be savedand associated with the data model for future use. The data model objectmay be used to perform searches of other data.

FIGS. 12, 13, and 7A-7D illustrate a series of user interface screenswhere a user may select report generation options using data models. Thereport generation process may be driven by a predefined data modelobject, such as a data model object defined and/or saved via a reportingapplication or a data model object obtained from another source. A usercan load a saved data model object using a report editor. For example,the initial search query and fields used to drive the report editor maybe obtained from a data model object. The data model object that is usedto drive a report generation process may define a search and a set offields. Upon loading of the data model object, the report generationprocess may enable a user to use the fields (e.g., the fields defined bythe data model object) to define criteria for a report (e.g., filters,split rows/columns, aggregates, etc.) and the search may be used toidentify events (e.g., to identify events responsive to the search) usedto generate the report. That is, for example, if a data model object isselected to drive a report editor, the graphical user interface of thereport editor may enable a user to define reporting criteria for thereport using the fields associated with the selected data model object,and the events used to generate the report may be constrained to theevents that match, or otherwise satisfy, the search constraints of theselected data model object.

The selection of a data model object for use in driving a reportgeneration may be facilitated by a data model object selectioninterface. FIG. 12 illustrates an example interactive data modelselection graphical user interface 1200 of a report editor that displaysa listing of available data models 1201. The user may select one of thedata models 1202.

FIG. 13 illustrates an example data model object selection graphicaluser interface 1300 that displays available data objects 1301 for theselected data object model 1202. The user may select one of thedisplayed data model objects 1302 for use in driving the reportgeneration process.

Once a data model object is selected by the user, a user interfacescreen 700 shown in FIG. 7A may display an interactive listing ofautomatic field identification options 701 based on the selected datamodel object. For example, a user may select one of the threeillustrated options (e.g., the “All Fields” option 702, the “SelectedFields” option 703, or the “Coverage” option (e.g., fields with at leasta specified % of coverage) 704). If the user selects the “All Fields”option 702, all of the fields identified from the events that werereturned in response to an initial search query may be selected. Thatis, for example, all of the fields of the identified data model objectfields may be selected. If the user selects the “Selected Fields” option703, only the fields from the fields of the identified data model objectfields that are selected by the user may be used. If the user selectsthe “Coverage” option 704, only the fields of the identified data modelobject fields meeting a specified coverage criteria may be selected. Apercent coverage may refer to the percentage of events returned by theinitial search query that a given field appears in. Thus, for example,if an object dataset includes 10,000 events returned in response to aninitial search query, and the “avg_age” field appears in 854 of those10,000 events, then the “avg_age” field would have a coverage of 8.54%for that object dataset. If, for example, the user selects the“Coverage” option and specifies a coverage value of 2%, only fieldshaving a coverage value equal to or greater than 2% may be selected. Thenumber of fields corresponding to each selectable option may bedisplayed in association with each option. For example, “97” displayednext to the “All Fields” option 702 indicates that 97 fields will beselected if the “All Fields” option is selected. The “3” displayed nextto the “Selected Fields” option 703 indicates that 3 of the 97 fieldswill be selected if the “Selected Fields” option is selected. The “49”displayed next to the “Coverage” option 704 indicates that 49 of the 97fields (e.g., the 49 fields having a coverage of 2% or greater) will beselected if the “Coverage” option is selected. The number of fieldscorresponding to the “Coverage” option may be dynamically updated basedon the specified percent of coverage.

FIG. 7B illustrates an example graphical user interface screen (alsocalled the pivot interface) 705 displaying the reporting application's“Report Editor” page. The screen may display interactive elements fordefining various elements of a report. For example, the page includes a“Filters” element 706, a “Split Rows” element 707, a “Split Columns”element 708, and a “Column Values” element 709. The page may include alist of search results 711. In this example, the Split Rows element 707is expanded, revealing a listing of fields 710 that can be used todefine additional criteria (e.g., reporting criteria). The listing offields 710 may correspond to the selected fields (attributes). That is,the listing of fields 710 may list only the fields previously selected,either automatically and/or manually by a user. FIG. 7C illustrates aformatting dialogue 712 that may be displayed upon selecting a fieldfrom the listing of fields 710. The dialogue can be used to format thedisplay of the results of the selection (e.g., label the column to bedisplayed as “component”).

FIG. 7D illustrates an example graphical user interface screen 705including a table of results 713 based on the selected criteriaincluding splitting the rows by the “component” field. A column 714having an associated count for each component listed in the table may bedisplayed that indicates an aggregate count of the number of times thatthe particular field-value pair (e.g., the value in a row) occurs in theset of events responsive to the initial search query.

FIG. 14 illustrates an example graphical user interface screen 1400 thatallows the user to filter search results and to perform statisticalanalysis on values extracted from specific fields in the set of events.In this example, the top ten product names ranked by price are selectedas a filter 1401 that causes the display of the ten most popularproducts sorted by price. Each row is displayed by product name andprice 1402. This results in each product displayed in a column labeled“product name” along with an associated price in a column labeled“price” 1406. Statistical analysis of other fields in the eventsassociated with the ten most popular products has been specified ascolumn values 1403. A count of the number of successful purchases foreach product is displayed in column 1404. This statistic may be producedby filtering the search results by the product name, finding alloccurrences of a successful purchase in a field within the events andgenerating a total of the number of occurrences. A sum of the totalsales is displayed in column 1405, which is a result of themultiplication of the price and the number of successful purchases foreach product.

The reporting application allows the user to create graphicalvisualizations of the statistics generated for a report. For example,FIG. 15 illustrates an example graphical user interface 1500 thatdisplays a set of components and associated statistics 1501. Thereporting application allows the user to select a visualization of thestatistics in a graph (e.g., bar chart, scatter plot, area chart, linechart, pie chart, radial gauge, marker gauge, filler gauge, etc.). FIG.16 illustrates an example of a bar chart visualization 1600 of an aspectof the statistical data 1501. FIG. 17 illustrates a scatter plotvisualization 1700 of an aspect of the statistical data 1501.

2.10. Acceleration Technique

The above-described system provides significant flexibility by enablinga user to analyze massive quantities of minimally processed data “on thefly” at search time instead of storing pre-specified portions of thedata in a database at ingestion time. This flexibility enables a user tosee valuable insights, correlate data, and perform subsequent queries toexamine interesting aspects of the data that may not have been apparentat ingestion time.

However, performing extraction and analysis operations at search timecan involve a large amount of data and require a large number ofcomputational operations, which can cause delays in processing thequeries. Advantageously, SPLUNK® ENTERPRISE system employs a number ofunique acceleration techniques that have been developed to speed upanalysis operations performed at search time. These techniques include:(1) performing search operations in parallel across multiple indexers;(2) using a keyword index; (3) using a high-performance analytics store;and (4) accelerating the process of generating reports. These noveltechniques are described in more detail below.

2.10.1. Aggregation Technique

To facilitate faster query processing, a query can be structured suchthat multiple indexers perform the query in parallel, while aggregationof search results from the multiple indexers is performed locally at thesearch head. For example, FIG. 8 illustrates how a search query 802received from a client at a search head 210 can split into two phases,including: (1) subtasks 804 (e.g., data retrieval or simple filtering)that may be performed in parallel by indexers 206 for execution, and (2)a search results aggregation operation 806 to be executed by the searchhead when the results are ultimately collected from the indexers.

During operation, upon receiving search query 802, a search head 210determines that a portion of the operations involved with the searchquery may be performed locally by the search head. The search headmodifies search query 802 by substituting “stats” (create aggregatestatistics over results sets received from the indexers at the searchhead) with “prestats” (create statistics by the indexer from localresults set) to produce search query 804, and then distributes searchquery 804 to distributed indexers, which are also referred to as “searchpeers.” Note that search queries may generally specify search criteriaor operations to be performed on events that meet the search criteria.Search queries may also specify field names, as well as search criteriafor the values in the fields or operations to be performed on the valuesin the fields. Moreover, the search head may distribute the full searchquery to the search peers as illustrated in FIG. 4, or may alternativelydistribute a modified version (e.g., a more restricted version) of thesearch query to the search peers. In this example, the indexers areresponsible for producing the results and sending them to the searchhead. After the indexers return the results to the search head, thesearch head aggregates the received results 806 to form a single searchresult set. By executing the query in this manner, the systemeffectively distributes the computational operations across the indexerswhile minimizing data transfers.

2.10.2. Keyword Index

As described above with reference to the flow charts in FIG. 3 and FIG.4, data intake and query system 108 can construct and maintain one ormore keyword indices to quickly identify events containing specifickeywords. This technique can greatly speed up the processing of queriesinvolving specific keywords. As mentioned above, to build a keywordindex, an indexer first identifies a set of keywords. Then, the indexerincludes the identified keywords in an index, which associates eachstored keyword with references to events containing that keyword, or tolocations within events where that keyword is located. When an indexersubsequently receives a keyword-based query, the indexer can access thekeyword index to quickly identify events containing the keyword.

2.10.3. High Performance Analytics Store

To speed up certain types of queries, some embodiments of system 108create a high-performance analytics store, which is referred to as a“summarization table,” that contains entries for specific field-valuepairs. Each of these entries keeps track of instances of a specificvalue in a specific field in the event data and includes references toevents containing the specific value in the specific field. For example,an example entry in a summarization table can keep track of occurrencesof the value “94107” in a “ZIP code” field of a set of events and theentry includes references to all of the events that contain the value“94107” in the ZIP code field. This optimization technique enables thesystem to quickly process queries that seek to determine how many eventshave a particular value for a particular field. To this end, the systemcan examine the entry in the summarization table to count instances ofthe specific value in the field without having to go through theindividual events or perform data extractions at search time. Also, ifthe system needs to process all events that have a specific field-valuecombination, the system can use the references in the summarizationtable entry to directly access the events to extract further informationwithout having to search all of the events to find the specificfield-value combination at search time.

In some embodiments, the system maintains a separate summarization tablefor each of the above-described time-specific buckets that stores eventsfor a specific time range. A bucket-specific summarization tableincludes entries for specific field-value combinations that occur inevents in the specific bucket. Alternatively, the system can maintain aseparate summarization table for each indexer. The indexer-specificsummarization table includes entries for the events in a data store thatare managed by the specific indexer. Indexer-specific summarizationtables may also be bucket-specific.

The summarization table can be populated by running a periodic querythat scans a set of events to find instances of a specific field-valuecombination, or alternatively instances of all field-value combinationsfor a specific field. A periodic query can be initiated by a user, orcan be scheduled to occur automatically at specific time intervals. Aperiodic query can also be automatically launched in response to a querythat asks for a specific field-value combination.

In some cases, when the summarization tables may not cover all of theevents that are relevant to a query, the system can use thesummarization tables to obtain partial results for the events that arecovered by summarization tables, but may also have to search throughother events that are not covered by the summarization tables to produceadditional results. These additional results can then be combined withthe partial results to produce a final set of results for the query. Thesummarization table and associated techniques are described in moredetail in U.S. Pat. No. 8,682,925, entitled “Distributed HighPerformance Analytics Store”, issued on 25 Mar. 2014, U.S. patentapplication Ser. No. 14/170,159, entitled “SUPPLEMENTING A HIGHPERFORMANCE ANALYTICS STORE WITH EVALUATION OF INDIVIDUAL EVENTS TORESPOND TO AN EVENT QUERY”, filed on 31 Jan. 2014, and U.S. patentapplication Ser. No. 14/815,973, entitled “STORAGE MEDIUM AND CONTROLDEVICE”, filed on 21 Feb. 2014, each of which is hereby incorporated byreference in its entirety.

2.10.4. Accelerating Report Generation

In some embodiments, a data server system such as the SPLUNK® ENTERPRISEsystem can accelerate the process of periodically generating updatedreports based on query results. To accelerate this process, asummarization engine automatically examines the query to determinewhether generation of updated reports can be accelerated by creatingintermediate summaries. If reports can be accelerated, the summarizationengine periodically generates a summary covering data obtained during alatest non-overlapping time period. For example, where the query seeksevents meeting a specified criterion, a summary for the time periodincludes only events within the time period that meet the specifiedcriteria. Similarly, if the query seeks statistics calculated from theevents, such as the number of events that match the specified criteria,then the summary for the time period includes the number of events inthe period that match the specified criteria.

In addition to the creation of the summaries, the summarization engineschedules the periodic updating of the report associated with the query.During each scheduled report update, the query engine determines whetherintermediate summaries have been generated covering portions of the timeperiod covered by the report update. If so, then the report is generatedbased on the information contained in the summaries. Also, if additionalevent data has been received and has not yet been summarized, and isrequired to generate the complete report, the query can be run on thisadditional event data. Then, the results returned by this query on theadditional event data, along with the partial results obtained from theintermediate summaries, can be combined to generate the updated report.This process is repeated each time the report is updated. Alternatively,if the system stores events in buckets covering specific time ranges,then the summaries can be generated on a bucket-by-bucket basis. Notethat producing intermediate summaries can save the work involved inre-running the query for previous time periods, so advantageously onlythe newer event data needs to be processed while generating an updatedreport. These report acceleration techniques are described in moredetail in U.S. Pat. No. 8,589,403, entitled “Compressed Journaling InEvent Tracking Files For Metadata Recovery And Replication”, issued on19 Nov. 2013, U.S. Pat. No. 8,412,696, entitled “Real Time Searching AndReporting”, issued on 2 Apr. 2011, and U.S. Pat. Nos. 8,589,375 and8,589,432, both also entitled “REAL TIME SEARCHING AND REPORTING”, bothissued on 19 Nov. 2013, each of which is hereby incorporated byreference in its entirety.

2.11. Security Features

The SPLUNK® ENTERPRISE platform provides various schemas, dashboards andvisualizations that simplify developers' task to create applicationswith additional capabilities. One such application is the SPLUNK® APPFOR ENTERPRISE SECURITY, which performs monitoring and alertingoperations and includes analytics to facilitate identifying both knownand unknown security threats based on large volumes of data stored bythe SPLUNK® ENTERPRISE system. SPLUNK® APP FOR ENTERPRISE SECURITYprovides the security practitioner with visibility intosecurity-relevant threats found in the enterprise infrastructure bycapturing, monitoring, and reporting on data from enterprise securitydevices, systems, and applications. Through the use of SPLUNK®ENTERPRISE searching and reporting capabilities, SPLUNK® APP FORENTERPRISE SECURITY provides a top-down and bottom-up view of anorganization's security posture.

The SPLUNK® APP FOR ENTERPRISE SECURITY leverages SPLUNK® ENTERPRISEsearch-time normalization techniques, saved searches, and correlationsearches to provide visibility into security-relevant threats andactivity and generate notable events for tracking. The App enables thesecurity practitioner to investigate and explore the data to find new orunknown threats that do not follow signature-based patterns.

Conventional Security Information and Event Management (SIEM) systemsthat lack the infrastructure to effectively store and analyze largevolumes of security-related data. Traditional SIEM systems typically usefixed schemas to extract data from pre-defined security-related fieldsat data ingestion time and storing the extracted data in a relationaldatabase. This traditional data extraction process (and associatedreduction in data size) that occurs at data ingestion time inevitablyhampers future incident investigations that may need original data todetermine the root cause of a security issue, or to detect the onset ofan impending security threat.

In contrast, the SPLUNK® APP FOR ENTERPRISE SECURITY system stores largevolumes of minimally processed security-related data at ingestion timefor later retrieval and analysis at search time when a live securitythreat is being investigated. To facilitate this data retrieval process,the SPLUNK® APP FOR ENTERPRISE SECURITY provides pre-specified schemasfor extracting relevant values from the different types ofsecurity-related event data and enables a user to define such schemas.

The SPLUNK® APP FOR ENTERPRISE SECURITY can process many types ofsecurity-related information. In general, this security-relatedinformation can include any information that can be used to identifysecurity threats. For example, the security-related information caninclude network-related information, such as IP addresses, domain names,asset identifiers, network traffic volume, uniform resource locatorstrings, and source addresses. The process of detecting security threatsfor network-related information is further described in U.S. Pat. No.8,826,434, entitled “SECURITY THREAT DETECTION BASED ON INDICATIONS INBIG DATA OF ACCESS TO NEWLY REGISTERED DOMAINS”, issued on 2 Sep. 2014,U.S. patent application Ser. No. 13/956,252, entitled “INVESTIGATIVE ANDDYNAMIC DETECTION OF POTENTIAL SECURITY-THREAT INDICATORS FROM EVENTS INBIG DATA”, filed on 31 Jul. 2013, U.S. patent application Ser. No.14/445,018, entitled “GRAPHIC DISPLAY OF SECURITY THREATS BASED ONINDICATIONS OF ACCESS TO NEWLY REGISTERED DOMAINS”, filed on 28 Jul.2014, U.S. patent application Ser. No. 14/445,023, entitled “SECURITYTHREAT DETECTION OF NEWLY REGISTERED DOMAINS”, filed on 28 Jul. 2014,U.S. patent application Ser. No. 14/815,971, entitled “SECURITY THREATDETECTION USING DOMAIN NAME ACCESSES”, filed on 1 Aug. 2015, and U.S.patent application Ser. No. 14/815,972, entitled “SECURITY THREATDETECTION USING DOMAIN NAME REGISTRATIONS”, filed on 1 Aug. 2015, eachof which is hereby incorporated by reference in its entirety for allpurposes. Security-related information can also include malwareinfection data and system configuration information, as well as accesscontrol information, such as login/logout information and access failurenotifications. The security-related information can originate fromvarious sources within a data center, such as hosts, virtual machines,storage devices and sensors. The security-related information can alsooriginate from various sources in a network, such as routers, switches,email servers, proxy servers, gateways, firewalls andintrusion-detection systems.

During operation, the SPLUNK® APP FOR ENTERPRISE SECURITY facilitatesdetecting “notable events” that are likely to indicate a securitythreat. These notable events can be detected in a number of ways: (1) auser can notice a correlation in the data and can manually identify acorresponding group of one or more events as “notable;” or (2) a usercan define a “correlation search” specifying criteria for a notableevent, and every time one or more events satisfy the criteria, theapplication can indicate that the one or more events are notable. A usercan alternatively select a pre-defined correlation search provided bythe application. Note that correlation searches can be run continuouslyor at regular intervals (e.g., every hour) to search for notable events.Upon detection, notable events can be stored in a dedicated “notableevents index,” which can be subsequently accessed to generate variousvisualizations containing security-related information. Also, alerts canbe generated to notify system operators when important notable eventsare discovered.

The SPLUNK® APP FOR ENTERPRISE SECURITY provides various visualizationsto aid in discovering security threats, such as a “key indicators view”that enables a user to view security metrics, such as counts ofdifferent types of notable events. For example, FIG. 9A illustrates anexample key indicators view 900 that comprises a dashboard, which candisplay a value 901, for various security-related metrics, such asmalware infections 902. It can also display a change in a metric value903, which indicates that the number of malware infections increased by63 during the preceding interval. Key indicators view 900 additionallydisplays a histogram panel 904 that displays a histogram of notableevents organized by urgency values, and a histogram of notable eventsorganized by time intervals. This key indicators view is described infurther detail in pending U.S. patent application Ser. No. 13/956,338,entitled “Key Indicators View”, filed on 31 Jul. 2013, and which ishereby incorporated by reference in its entirety for all purposes.

These visualizations can also include an “incident review dashboard”that enables a user to view and act on “notable events.” These notableevents can include: (1) a single event of high importance, such as anyactivity from a known web attacker; or (2) multiple events thatcollectively warrant review, such as a large number of authenticationfailures on a host followed by a successful authentication. For example,FIG. 9B illustrates an example incident review dashboard 910 thatincludes a set of incident attribute fields 911 that, for example,enables a user to specify a time range field 912 for the displayedevents. It also includes a timeline 913 that graphically illustrates thenumber of incidents that occurred in time intervals over the selectedtime range. It additionally displays an events list 914 that enables auser to view a list of all of the notable events that match the criteriain the incident attributes fields 911. To facilitate identifyingpatterns among the notable events, each notable event can be associatedwith an urgency value (e.g., low, medium, high, critical), which isindicated in the incident review dashboard. The urgency value for adetected event can be determined based on the severity of the event andthe priority of the system component associated with the event.

2.12. Data Center Monitoring

As mentioned above, the SPLUNK® ENTERPRISE platform provides variousfeatures that simplify the developer's task to create variousapplications. One such application is SPLUNK® APP FOR VMWARE® thatprovides operational visibility into granular performance metrics, logs,tasks and events, and topology from hosts, virtual machines and virtualcenters. It empowers administrators with an accurate real-time pictureof the health of the environment, proactively identifying performanceand capacity bottlenecks.

Conventional data-center-monitoring systems lack the infrastructure toeffectively store and analyze large volumes of machine-generated data,such as performance information and log data obtained from the datacenter. In conventional data-center-monitoring systems,machine-generated data is typically pre-processed prior to being stored,for example, by extracting pre-specified data items and storing them ina database to facilitate subsequent retrieval and analysis at searchtime. However, the rest of the data is not saved and discarded duringpre-processing.

In contrast, the SPLUNK® APP FOR VMWARE® stores large volumes ofminimally processed machine data, such as performance information andlog data, at ingestion time for later retrieval and analysis at searchtime when a live performance issue is being investigated. In addition todata obtained from various log files, this performance-relatedinformation can include values for performance metrics obtained throughan application programming interface (API) provided as part of thevSphere Hypervisor™ system distributed by VMware, Inc. of Palo Alto,Calif. For example, these performance metrics can include: (1)CPU-related performance metrics; (2) disk-related performance metrics;(3) memory-related performance metrics; (4) network-related performancemetrics; (5) energy-usage statistics; (6) data-traffic-relatedperformance metrics; (7) overall system availability performancemetrics; (8) cluster-related performance metrics; and (9) virtualmachine performance statistics. Such performance metrics are describedin U.S. patent application Ser. No. 14/167,316, entitled “CorrelationFor User-Selected Time Ranges Of Values For Performance Metrics OfComponents In An Information-Technology Environment With Log Data FromThat Information-Technology Environment”, filed on 29 Jan. 2014, andwhich is hereby incorporated by reference in its entirety for allpurposes.

To facilitate retrieving information of interest from performance dataand log files, the SPLUNK® APP FOR VMWARE® provides pre-specifiedschemas for extracting relevant values from different types ofperformance-related event data, and also enables a user to define suchschemas.

The SPLUNK® APP FOR VMWARE® additionally provides various visualizationsto facilitate detecting and diagnosing the root cause of performanceproblems. For example, one such visualization is a “proactive monitoringtree” that enables a user to easily view and understand relationshipsamong various factors that affect the performance of a hierarchicallystructured computing system. This proactive monitoring tree enables auser to easily navigate the hierarchy by selectively expanding nodesrepresenting various entities (e.g., virtual centers or computingclusters) to view performance information for lower-level nodesassociated with lower-level entities (e.g., virtual machines or hostsystems). Example node-expansion operations are illustrated in FIG. 9C,wherein nodes 933 and 934 are selectively expanded. Note that nodes931-939 can be displayed using different patterns or colors to representdifferent performance states, such as a critical state, a warning state,a normal state or an unknown/offline state. The ease of navigationprovided by selective expansion in combination with the associatedperformance-state information enables a user to quickly diagnose theroot cause of a performance problem. The proactive monitoring tree isdescribed in further detail in U.S. patent application Ser. No.14/253,490, entitled “PROACTIVE MONITORING TREE WITH SEVERITY STATESORTING”, filed on 15 Apr. 2014, and U.S. patent application Ser. No.14/812,948, also entitled “PROACTIVE MONITORING TREE WITH SEVERITY STATESORTING”, filed on 29 Jul. 2015, each of which is hereby incorporated byreference in its entirety for all purposes.

The SPLUNK® APP FOR VMWARE® also provides a user interface that enablesa user to select a specific time range and then view heterogeneous datacomprising events, log data, and associated performance metrics for theselected time range. For example, the screen illustrated in FIG. 9Ddisplays a listing of recent “tasks and events” and a listing of recent“log entries” for a selected time range above a performance-metric graphfor “average CPU core utilization” for the selected time range. Notethat a user is able to operate pull-down menus 942 to selectivelydisplay different performance metric graphs for the selected time range.This enables the user to correlate trends in the performance-metricgraph with corresponding event and log data to quickly determine theroot cause of a performance problem. This user interface is described inmore detail in U.S. patent application Ser. No. 14/167,316, entitled“Correlation For User-Selected Time Ranges Of Values For PerformanceMetrics Of Components In An Information-Technology Environment With LogData From That Information-Technology Environment”, filed on 29 Jan.2014, and which is hereby incorporated by reference in its entirety forall purposes.

2.13. Cloud-Based System Overview

The example data intake and query system 108 described in reference toFIG. 2 comprises several system components, including one or moreforwarders, indexers, and search heads. In some environments, a user ofa data intake and query system 108 may install and configure, oncomputing devices owned and operated by the user, one or more softwareapplications that implement some or all of these system components. Forexample, a user may install a software application on server computersowned by the user and configure each server to operate as one or more ofa forwarder, an indexer, a search head, etc. This arrangement generallymay be referred to as an “on-premises” solution. That is, the system 108is installed and operates on computing devices directly controlled bythe user of the system. Some users may prefer an on-premises solutionbecause it may provide a greater level of control over the configurationof certain aspects of the system (e.g., security, privacy, standards,controls, etc.). However, other users may instead prefer an arrangementin which the user is not directly responsible for providing and managingthe computing devices upon which various components of system 108operate.

In one embodiment, to provide an alternative to an entirely on-premisesenvironment for system 108, one or more of the components of a dataintake and query system instead may be provided as a cloud-basedservice. In this context, a cloud-based service refers to a servicehosted by one more computing resources that are accessible to end usersover a network, for example, by using a web browser or other applicationon a client device to interface with the remote computing resources. Forexample, a service provider may provide a cloud-based data intake andquery system by managing computing resources configured to implementvarious aspects of the system (e.g., forwarders, indexers, search heads,etc.) and by providing access to the system to end users via a network.Typically, a user may pay a subscription or other fee to use such aservice. Each subscribing user of the cloud-based service may beprovided with an account that enables the user to configure a customizedcloud-based system based on the user's preferences.

FIG. 10 illustrates a block diagram of an example cloud-based dataintake and query system. Similar to the system of FIG. 2, the networkedcomputer system 1000 includes input data sources 202 and forwarders 204.These input data sources and forwarders may be in a subscriber's privatecomputing environment. Alternatively, they might be directly managed bythe service provider as part of the cloud service. In the example system1000, one or more forwarders 204 and client devices 1002 are coupled toa cloud-based data intake and query system 1006 via one or more networks1004. Network 1004 broadly represents one or more LANs, WANs, cellularnetworks, intranet, internet, etc., using any of wired, wireless,terrestrial microwave, satellite links, etc., and may include the publicInternet, and is used by client devices 1002 and forwarders 204 toaccess the system 1006. Similar to the system of 108, each of theforwarders 204 may be configured to receive data from an input sourceand to forward the data to other components of the system 1006 forfurther processing.

In an embodiment, a cloud-based data intake and query system 1006 maycomprise a plurality of system instances 1008. In general, each systeminstance 1008 may include one or more computing resources managed by aprovider of the cloud-based system 1006 made available to a particularsubscriber. The computing resources comprising a system instance 1008may, for example, include one or more servers or other devicesconfigured to implement one or more forwarders, indexers, search heads,and other components of a data intake and query system, similar tosystem 108. As indicated above, a subscriber may use a web browser orother application of a client device 1002 to access a web portal orother interface that enables the subscriber to configure an instance1008.

Providing a data intake and query system as described in reference tosystem 108 as a cloud-based service presents a number of challenges.Each of the components of a system 108 (e.g., forwarders, indexers andsearch heads) may at times refer to various configuration files storedlocally at each component. These configuration files typically mayinvolve some level of user configuration to accommodate particular typesof data a user desires to analyze and to account for other userpreferences. However, in a cloud-based service context, users typicallymay not have direct access to the underlying computing resourcesimplementing the various system components (e.g., the computingresources comprising each system instance 1008) and may desire to makesuch configurations indirectly, for example, using one or more web-basedinterfaces. Thus, the techniques and systems described herein forproviding user interfaces that enable a user to configure source typedefinitions are applicable to both on-premises and cloud-based servicecontexts, or some combination thereof (e.g., a hybrid system where bothan on-premises environment such as SPLUNK® ENTERPRISE and a cloud-basedenvironment such as SPLUNK CLOUD™ are centrally visible).

2.14. Searching Externally Archived Data

FIG. 11 shows a block diagram of an example of a data intake and querysystem 108 that provides transparent search facilities for data systemsthat are external to the data intake and query system. Such facilitiesare available in the HUNK® system provided by Splunk Inc. of SanFrancisco, Calif. HUNK® represents an analytics platform that enablesbusiness and IT teams to rapidly explore, analyze, and visualize data inHadoop and NoSQL data stores.

The search head 210 of the data intake and query system receives searchrequests from one or more client devices 1104 over network connections1120. As discussed above, the data intake and query system 108 mayreside in an enterprise location, in the cloud, etc. FIG. 11 illustratesthat multiple client devices 1104 a, 1104 b, . . . , 1104 n maycommunicate with the data intake and query system 108. The clientdevices 1104 may communicate with the data intake and query system usinga variety of connections. For example, one client device in FIG. 11 isillustrated as communicating over an Internet (Web) protocol, anotherclient device is illustrated as communicating via a command lineinterface, and another client device is illustrated as communicating viaa system developer kit (SDK).

The search head 210 analyzes the received search request to identifyrequest parameters. If a search request received from one of the clientdevices 1104 references an index maintained by the data intake and querysystem, then the search head 210 connects to one or more indexers 206 ofthe data intake and query system for the index referenced in the requestparameters. That is, if the request parameters of the search requestreference an index, then the search head accesses the data in the indexvia the indexer. The data intake and query system 108 may include one ormore indexers 206, depending on system access resources andrequirements. As described further below, the indexers 206 retrieve datafrom their respective local data stores 208 as specified in the searchrequest. The indexers and their respective data stores can comprise oneor more storage devices and typically reside on the same system, thoughthey may be connected via a local network connection.

If the request parameters of the received search request reference anexternal data collection, which is not accessible to the indexers 206 orunder the management of the data intake and query system, then thesearch head 210 can access the external data collection through anExternal Result Provider (ERP) process 1110. An external data collectionmay be referred to as a “virtual index” (plural, “virtual indices”). AnERP process provides an interface through which the search head 210 mayaccess virtual indices.

Thus, a search reference to an index of the system relates to a locallystored and managed data collection. In contrast, a search reference to avirtual index relates to an externally stored and managed datacollection, which the search head may access through one or more ERPprocesses 1110, 1112. FIG. 11 shows two ERP processes 1110, 1112 thatconnect to respective remote (external) virtual indices, which areindicated as a Hadoop or another system 1114 (e.g., Amazon S3, AmazonEMR, other Hadoop Compatible File Systems (HCFS), etc.) and a relationaldatabase management system (RDBMS) 1116. Other virtual indices mayinclude other file organizations and protocols, such as Structured QueryLanguage (SQL) and the like. The ellipses between the ERP processes1110, 1112 indicate optional additional ERP processes of the data intakeand query system 108. An ERP process may be a computer process that isinitiated or spawned by the search head 210 and is executed by thesearch data intake and query system 108. Alternatively, or additionally,an ERP process may be a process spawned by the search head 210 on thesame or different host system as the search head 210 resides.

The search head 210 may spawn a single ERP process in response tomultiple virtual indices referenced in a search request, or the searchhead may spawn different ERP processes for different virtual indices.Generally, virtual indices that share common data configurations orprotocols may share ERP processes. For example, all search queryreferences to a Hadoop file system may be processed by the same ERPprocess, if the ERP process is suitably configured. Likewise, all searchquery references to an SQL database may be processed by the same ERPprocess. In addition, the search head may provide a common ERP processfor common external data source types (e.g., a common vendor may utilizea common ERP process, even if the vendor includes different data storagesystem types, such as Hadoop and SQL). Common indexing schemes also maybe handled by common ERP processes, such as flat text files or Weblogfiles.

The search head 210 determines the number of ERP processes to beinitiated via the use of configuration parameters that are included in asearch request message. Generally, there is a one-to-many relationshipbetween an external results provider “family” and ERP processes. Thereis also a one-to-many relationship between an ERP process andcorresponding virtual indices that are referred to in a search request.For example, using RDBMS, assume two independent instances of such asystem by one vendor, such as one RDBMS for production and another RDBMSused for development. In such a situation, it is likely preferable (butoptional) to use two ERP processes to maintain the independent operationas between production and development data. Both of the ERPs, however,will belong to the same family, because the two RDBMS system types arefrom the same vendor.

The ERP processes 1110, 1112 receive a search request from the searchhead 210. The search head may optimize the received search request forexecution at the respective external virtual index. Alternatively, theERP process may receive a search request as a result of analysisperformed by the search head or by a different system process. The ERPprocesses 1110, 1112 can communicate with the search head 210 viaconventional input/output routines (e.g., standard in/standard out,etc.). In this way, the ERP process receives the search request from aclient device such that the search request may be efficiently executedat the corresponding external virtual index.

The ERP processes 1110, 1112 may be implemented as a process of the dataintake and query system. Each ERP process may be provided by the dataintake and query system, or may be provided by process or applicationproviders who are independent of the data intake and query system. Eachrespective ERP process may include an interface application installed ata computer of the external result provider that ensures propercommunication between the search support system and the external resultprovider. The ERP processes 1110, 1112 generate appropriate searchrequests in the protocol and syntax of the respective virtual indices1114, 1116, each of which corresponds to the search request received bythe search head 210. Upon receiving search results from theircorresponding virtual indices, the respective ERP process passes theresult to the search head 210, which may return or display the resultsor a processed set of results based on the returned results to therespective client device.

Client devices 1104 may communicate with the data intake and querysystem 108 through a network interface 1120, e.g., one or more LANs,WANs, cellular networks, intranet, and/or internet using any of wired,wireless, terrestrial microwave, satellite links, etc., and may includethe public Internet.

The analytics platform utilizing the External Result Provider processdescribed in more detail in U.S. Pat. No. 8,738,629, entitled “ExternalResult Provided Process For RetriEving Data Stored Using A DifferentConfiguration Or Protocol”, issued on 27 May 2014, U.S. Pat. No.8,738,587, entitled “PROCESSING A SYSTEM SEARCH REQUEST BY RETRIEVINGRESULTS FROM BOTH A NATIVE INDEX AND A VIRTUAL INDEX”, issued on 25 Jul.2013, U.S. patent application Ser. No. 14/266,832, entitled “PROCESSINGA SYSTEM SEARCH REQUEST ACROSS DISPARATE DATA COLLECTION SYSTEMS”, filedon 1 May 2014, and U.S. patent application Ser. No. 14/449,144, entitled“PROCESSING A SYSTEM SEARCH REQUEST INCLUDING EXTERNAL DATA SOURCES”,filed on 31 Jul. 2014, each of which is hereby incorporated by referencein its entirety for all purposes.

2.14.1. ERP Process Features

The ERP processes described above may include two operation modes: astreaming mode and a reporting mode. The ERP processes can operate instreaming mode only, in reporting mode only, or in both modessimultaneously. Operating in both modes simultaneously is referred to asmixed mode operation. In a mixed mode operation, the ERP at some pointcan stop providing the search head with streaming results and onlyprovide reporting results thereafter, or the search head at some pointmay start ignoring streaming results it has been using and only usereporting results thereafter.

The streaming mode returns search results in real time, with minimalprocessing, in response to the search request. The reporting modeprovides results of a search request with processing of the searchresults prior to providing them to the requesting search head, which inturn provides results to the requesting client device. ERP operationwith such multiple modes provides greater performance flexibility withregard to report time, search latency, and resource utilization.

In a mixed mode operation, both streaming mode and reporting mode areoperating simultaneously. The streaming mode results (e.g., the raw dataobtained from the external data source) are provided to the search head,which can then process the results data (e.g., break the raw data intoevents, timestamp it, filter it, etc.) and integrate the results datawith the results data from other external data sources, and/or from datastores of the search head. The search head performs such processing andcan immediately start returning interim (streaming mode) results to theuser at the requesting client device; simultaneously, the search head iswaiting for the ERP process to process the data it is retrieving fromthe external data source as a result of the concurrently executingreporting mode.

In some instances, the ERP process initially operates in a mixed mode,such that the streaming mode operates to enable the ERP quickly toreturn interim results (e.g., some of the raw or unprocessed datanecessary to respond to a search request) to the search head, enablingthe search head to process the interim results and begin providing tothe client or search requester interim results that are responsive tothe query. Meanwhile, in this mixed mode, the ERP also operatesconcurrently in reporting mode, processing portions of raw data in amanner responsive to the search query. Upon determining that it hasresults from the reporting mode available to return to the search head,the ERP may halt processing in the mixed mode at that time (or somelater time) by stopping the return of data in streaming mode to thesearch head and switching to reporting mode only. The ERP at this pointstarts sending interim results in reporting mode to the search head,which in turn may then present this processed data responsive to thesearch request to the client or search requester. Typically, the searchhead switches from using results from the ERP's streaming mode ofoperation to results from the ERP's reporting mode of operation when thehigher bandwidth results from the reporting mode outstrip the amount ofdata processed by the search head in the streaming mode of ERPoperation.

A reporting mode may have a higher bandwidth because the ERP does nothave to spend time transferring data to the search head for processingall the raw data. In addition, the ERP may optionally direct anotherprocessor to do the processing.

The streaming mode of operation does not need to be stopped to gain thehigher bandwidth benefits of a reporting mode; the search head couldsimply stop using the streaming mode results—and start using thereporting mode results—when the bandwidth of the reporting mode hascaught up with or exceeded the amount of bandwidth provided by thestreaming mode. Thus, a variety of triggers and ways to accomplish asearch head's switch from using streaming mode results to usingreporting mode results may be appreciated by one skilled in the art.

The reporting mode can involve the ERP process (or an external system)performing event breaking, time stamping, filtering of events to matchthe search query request, and calculating statistics on the results. Theuser can request particular types of data, such as if the search queryitself involves types of events, or the search request may ask forstatistics on data, such as on events that meet the search request. Ineither case, the search head understands the query language used in thereceived query request, which may be a proprietary language. One examplequery language is Splunk Processing Language (SPL) developed by theassignee of the application, Splunk Inc. The search head typicallyunderstands how to use that language to obtain data from the indexers,which store data in a format used by the SPLUNK® Enterprise system.

The ERP processes support the search head, as the search head is notordinarily configured to understand the format in which data is storedin external data sources such as Hadoop or SQL data systems. Rather, theERP process performs that translation from the query submitted in thesearch support system's native format (e.g., SPL if SPLUNK® ENTERPRISEis used as the search support system) to a search query request formatthat will be accepted by the corresponding external data system. Theexternal data system typically stores data in a different format fromthat of the search support system's native index format, and it utilizesa different query language (e.g., SQL or MapReduce, rather than SPL orthe like).

As noted, the ERP process can operate in the streaming mode alone. Afterthe ERP process has performed the translation of the query request andreceived raw results from the streaming mode, the search head canintegrate the returned data with any data obtained from local datasources (e.g., native to the search support system), other external datasources, and other ERP processes (if such operations were required tosatisfy the terms of the search query). An advantage of mixed modeoperation is that, in addition to streaming mode, the ERP process isalso executing concurrently in reporting mode. Thus, the ERP process(rather than the search head) is processing query results (e.g.,performing event breaking, timestamping, filtering, possibly calculatingstatistics if required to be responsive to the search query request,etc.). It should be apparent to those skilled in the art that additionaltime is needed for the ERP process to perform the processing in such aconfiguration. Therefore, the streaming mode will allow the search headto start returning interim results to the user at the client devicebefore the ERP process can complete sufficient processing to startreturning any search results. The switchover between streaming andreporting mode happens when the ERP process determines that theswitchover is appropriate, such as when the ERP process determines itcan begin returning meaningful results from its reporting mode.

The operation described above illustrates the source of operationallatency: streaming mode has low latency (immediate results) and usuallyhas relatively low bandwidth (fewer results can be returned per unit oftime). In contrast, the concurrently running reporting mode hasrelatively high latency (it has to perform a lot more processing beforereturning any results) and usually has relatively high bandwidth (moreresults can be processed per unit of time). For example, when the ERPprocess does begin returning report results, it returns more processedresults than in the streaming mode, because, e.g., statistics only needto be calculated to be responsive to the search request. That is, theERP process doesn't have to take time to first return raw data to thesearch head. As noted, the ERP process could be configured to operate instreaming mode alone and return just the raw data for the search head toprocess in a way that is responsive to the search request.Alternatively, the ERP process can be configured to operate in thereporting mode only. Also, the ERP process can be configured to operatein streaming mode and reporting mode concurrently, as described, withthe ERP process stopping the transmission of streaming results to thesearch head when the concurrently running reporting mode has caught upand started providing results. The reporting mode does not require theprocessing of all raw data that is responsive to the search queryrequest before the ERP process starts returning results; rather, thereporting mode usually performs processing of chunks of events andreturns the processing results to the search head for each chunk.

For example, an ERP process can be configured to merely return thecontents of a search result file verbatim, with little or no processingof results. That way, the search head performs all processing (such asparsing byte streams into events, filtering, etc.). The ERP process canbe configured to perform additional intelligence, such as analyzing thesearch request and handling all the computation that a native searchindexer process would otherwise perform. In this way, the configured ERPprocess provides greater flexibility in features while operatingaccording to desired preferences, such as response latency and resourcerequirements.

2.14. IT Service Monitoring

As previously mentioned, the SPLUNK® ENTERPRISE platform providesvarious schemas, dashboards and visualizations that make it easy fordevelopers to create applications to provide additional capabilities.One such application is SPLUNK® IT SERVICE INTELLIGENCE™, which performsmonitoring and alerting operations. It also includes analytics to helpan analyst diagnose the root cause of performance problems based onlarge volumes of data stored by the SPLUNK® ENTERPRISE system ascorrelated to the various services an IT organization provides (aservice-centric view). This differs significantly from conventional ITmonitoring systems that lack the infrastructure to effectively store andanalyze large volumes of service-related event data. Traditional servicemonitoring systems typically use fixed schemas to extract data frompre-defined fields at data ingestion time, wherein the extracted data istypically stored in a relational database. This data extraction processand associated reduction in data content that occurs at data ingestiontime inevitably hampers future investigations, when all of the originaldata may be needed to determine the root cause of or contributingfactors to a service issue.

In contrast, a SPLUNK® IT SERVICE INTELLIGENCE™ system stores largevolumes of minimally-processed service-related data at ingestion timefor later retrieval and analysis at search time, to perform regularmonitoring, or to investigate a service issue. To facilitate this dataretrieval process, SPLUNK® IT SERVICE INTELLIGENCE™ enables a user todefine an IT operations infrastructure from the perspective of theservices it provides. In this service-centric approach, a service suchas corporate e-mail may be defined in terms of the entities employed toprovide the service, such as host machines and network devices. Eachentity is defined to include information for identifying all of theevent data that pertains to the entity, whether produced by the entityitself or by another machine, and considering the many various ways theentity may be identified in raw machine data (such as by a URL, an IPaddress, or machine name). The service and entity definitions canorganize event data around a service so that all of the event datapertaining to that service can be easily identified. This capabilityprovides a foundation for the implementation of Key PerformanceIndicators.

One or more Key Performance Indicators (KPI's) are defined for a servicewithin the SPLUNK® IT SERVICE INTELLIGENCE™ application. Each KPImeasures an aspect of service performance at a point in time or over aperiod of time (aspect KPI's). Each KPI is defined by a search querythat derives a KPI value from the machine data of events associated withthe entities that provide the service. Information in the entitydefinitions may be used to identify the appropriate events at the time aKPI is defined or whenever a KPI value is being determined. The KPIvalues derived over time may be stored to build a valuable repository ofcurrent and historical performance information for the service, and therepository, itself, may be subject to search query processing. AggregateKPIs may be defined to provide a measure of service performancecalculated from a set of service aspect KPI values; this aggregate mayeven be taken across defined timeframes and/or across multiple services.A particular service may have an aggregate KPI derived fromsubstantially all of the aspect KPI's of the service to indicate anoverall health score for the service.

SPLUNK® IT SERVICE INTELLIGENCE™ facilitates the production ofmeaningful aggregate KPI's through a system of KPI thresholds and statevalues. Different KPI definitions may produce values in differentranges, and so the same value may mean something very different from oneKPI definition to another. To address this, SPLUNK® IT SERVICEINTELLIGENCE™ implements a translation of individual KPI values to acommon domain of “state” values. For example, a KPI range of values maybe 1-100, or 50-275, while values in the state domain may be ‘critical,’‘warning,’ ‘normal,’ and ‘informational’. Thresholds associated with aparticular KPI definition determine ranges of values for that KPI thatcorrespond to the various state values. In one case, KPI values 95-100may be set to correspond to ‘critical’ in the state domain. KPI valuesfrom disparate KPI's can be processed uniformly once they are translatedinto the common state values using the thresholds. For example, “normal80% of the time” can be applied across various KPI's. To providemeaningful aggregate KPI's, a weighting value can be assigned to eachKPI so that its influence on the calculated aggregate KPI value isincreased or decreased relative to the other KPI's.

One service in an IT environment often impacts, or is impacted by,another service. SPLUNK® IT SERVICE INTELLIGENCE™ can reflect thesedependencies. For example, a dependency relationship between a corporatee-mail service and a centralized authentication service can be reflectedby recording an association between their respective servicedefinitions. The recorded associations establish a service dependencytopology that informs the data or selection options presented in a GUI,for example. (The service dependency topology is like a “map” showinghow services are connected based on their dependencies.) The servicetopology may itself be depicted in a GUI and may be interactive to allownavigation among related services.

Entity definitions in SPLUNK® IT SERVICE INTELLIGENCE™ can includeinformational fields that can serve as metadata, implied data fields, orattributed data fields for the events identified by other aspects of theentity definition. Entity definitions in SPLUNK® IT SERVICEINTELLIGENCE™ can also be created and updated by an import of tabulardata (as represented in a CSV, another delimited file, or a search queryresult set). The import may be GUI-mediated or processed using importparameters from a GUI-based import definition process. Entitydefinitions in SPLUNK® IT SERVICE INTELLIGENCE™ can also be associatedwith a service by means of a service definition rule. Processing therule results in the matching entity definitions being associated withthe service definition. The rule can be processed at creation time, andthereafter on a scheduled or on-demand basis. This allows dynamic,rule-based updates to the service definition.

During operation, SPLUNK® IT SERVICE INTELLIGENCE™ can recognizeso-called “notable events” that may indicate a service performanceproblem or other situation of interest. These notable events can berecognized by a “correlation search” specifying trigger criteria for anotable event: every time KPI values satisfy the criteria, theapplication indicates a notable event. A severity level for the notableevent may also be specified. Furthermore, when trigger criteria aresatisfied, the correlation search may additionally or alternativelycause a service ticket to be created in an IT service management (ITSM)system, such as a system available from ServiceNow, Inc., of SantaClara, Calif.

SPLUNK® IT SERVICE INTELLIGENCE™ provides various visualizations builton its service-centric organization of event data and the KPI valuesgenerated and collected. Visualizations can be particularly useful formonitoring or investigating service performance. SPLUNK® IT SERVICEINTELLIGENCE™ provides a service monitoring interface suitable as thehome page for ongoing IT service monitoring. The interface isappropriate for settings such as desktop use or for a wall-mounteddisplay in a network operations center (NOC). The interface mayprominently display a services health section with tiles for theaggregate KPI's indicating overall health for defined services and ageneral KPI section with tiles for KPI's related to individual serviceaspects. These tiles may display KPI information in a variety of ways,such as by being colored and ordered according to factors like the KPIstate value. They also can be interactive and navigate to visualizationsof more detailed KPI information.

SPLUNK® IT SERVICE INTELLIGENCE™ provides a service-monitoring dashboardvisualization based on a user-defined template. The template can includeuser-selectable widgets of varying types and styles to display KPIinformation. The content and the appearance of widgets can responddynamically to changing KPI information. The KPI widgets can appear inconjunction with a background image, user drawing objects, or othervisual elements, that depict the IT operations environment, for example.The KPI widgets or other GUI elements can be interactive so as toprovide navigation to visualizations of more detailed KPI information.

SPLUNK® IT SERVICE INTELLIGENCE™ provides a visualization showingdetailed time-series information for multiple KPI's in parallel graphlanes. The length of each lane can correspond to a uniform time range,while the width of each lane may be automatically adjusted to fit thedisplayed KPI data. Data within each lane may be displayed in a userselectable style, such as a line, area, or bar chart. During operation,a user may select a position in the time range of the graph lanes toactivate lane inspection at that point in time. Lane inspection maydisplay an indicator for the selected time across the graph lanes anddisplay the KPI value associated with that point in time for each of thegraph lanes. The visualization may also provide navigation to aninterface for defining a correlation search, using information from thevisualization to pre-populate the definition.

SPLUNK® IT SERVICE INTELLIGENCE™ provides a visualization for incidentreview showing detailed information for notable events. The incidentreview visualization may also show summary information for the notableevents over a time frame, such as an indication of the number of notableevents at each of a number of severity levels. The severity leveldisplay may be presented as a rainbow chart with the warmest colorassociated with the highest severity classification. The incident reviewvisualization may also show summary information for the notable eventsover a time frame, such as the number of notable events occurring withinsegments of the time frame. The incident review visualization maydisplay a list of notable events within the time frame ordered by anynumber of factors, such as time or severity. The selection of aparticular notable event from the list may display detailed informationabout that notable event, including an identification of the correlationsearch that generated the notable event.

SPLUNK® IT SERVICE INTELLIGENCE™ provides pre-specified schemas forextracting relevant values from the different types of service-relatedevent data. It also enables a user to define such schemas.

3.0 Data Manipulation Pipeline Optimization

Turning to FIG. 18, FIG. 18 shows a pipeline manager 1800 in accordancewith one or more embodiments of the invention. The pipeline manager 1800is implemented on or may be a computing system, and includesfunctionality to receive and execute pipelines. In general, a pipelineis a sequence of commands, whereby each command is in a particularorder. Each command in the sequence is ordered such that the output of aprevious command is an input to the next command. For example, theoutput of the immediately preceding command may be the input to theimmediate next commend. The particular order is preset prior toexecution. Thus, the order of the commands in the sequence isindependent of the execution.

In one or more embodiments, the pipeline is defined by an end user andsubmitted to an end user application. For example, the pipeline may besubmitted via a text box. Each command in the sequence of commands has acommand identifier and any parameters of the command. The commandidentifier uniquely identifies a type of command to perform. In otherwords, the command identifier identifies the set of instructions toperform. The parameters are any input controls specifying how to performthe operation. Execution of the command may further use input data. Theinput data may be the results of the previously processed command.

By way of an example, consider the scenario in which a data set has theattributes a, b, and c, where each event in the data set has a value forattributes a, b, and c. The data set may have been acquired throughexecution of a prior command in the pipeline. In such a scenario, acommand in the pipeline may be “Add (a, c, d)”, where the last parameterof the add command refers to the location of storage, and the first twoparameters refers to the values to add. In such a scenario, the commandidentifier is “Add”, the parameters are “a,” “c,” and “d,” and the dataset is the input, where the data set is separately provided from thepipeline. The command identifier refers to the set of instructions that,for each event, performs the operation “value of attribute d=value ofattribute a+value of attribute c.”

For example, the pipeline may be a query evaluation pipeline thatobtains and processes data from a data store, such as the data storedescribed in FIG. 2. In such a scenario, the query evaluation pipelinemay include a search command, an evaluation command, a statisticscommand, and/or other commands. By way of another example, the pipelinemay be a data processing pipeline, whereby an end user provides asequence of commands for execution on a user-provided data set. Otherpipelines may be processed by the pipeline manager 1800 withoutdeparting from the scope of the invention.

Continuing with FIG. 18, the pipeline interface 1802 is an interface forreceiving the pipeline. For example, the pipeline interface 1802 may bea graphical user interface of a web application, a graphical userinterface of a local application, an application programming interface,or another interface. For example, the pipeline interface may be all orpart of a report generation interface described above. The pipelineinterface may encompass or be a part of any other interface describedherein.

In one or more embodiments, the pipeline interface 1802 is a text boxthat is configured to receive a pipeline. Each command in the pipelinemay be distinguished from other commands using a delimiter, such as apipe character, semicolon, colon, tab, or other predefined character. Byway of another example, the pipeline interface may be a sequence of textboxes or other input fields for submitting commands. Each user interfacewidget in the sequence may be configured to receive a command. The orderof widgets may define the order of the commands in the sequence.

In one or more embodiments of the invention, commands are executed bycommand processors 1804. A command processor may be hardware, software,firmware, or any combination thereof. The command processor includesinstructions for executing a command when provided with the parametersof the command. In one or more embodiments, each command processor 1804is specific to the type of command. In other words, the commandprocessor has a one to one correspondence with possible commandidentifiers that may be in the pipeline. In other embodiments, thecommand processor may match multiple command identifiers. The commandprocessor is configured to receive a request to execute a command, wherethe request includes parameters, and execute the instructions of thecommand processor using the parameters. At least some of the commandprocessors may further use input data that is separately provided fromthe command in the pipeline, such as from a prior command. The commandprocessor 1804 further includes functionality to return results fromexecuting a command. The command processor may be predefined by thesystem and distributed with the pipeline manager, created by aninformation technology specialist, created by a software developer afterthe pipeline manager is distributed (e.g., as a plug in to the pipelinemanager), or by another. Further, although only two command processorsare shown, more command processors may exist without departing from thescope of the invention.

Continuing with FIG. 18, a command execution manager 1806 is configuredto parse commands in a pipeline and send the commands to thecorresponding command processors. In other words, the command executionmanager 1806 includes functionality to issue a call to the correspondingcommand processor that matches the command identifier of the command inthe pipeline, where the call includes the parameters of the command. Inone or more embodiments, the command execution manager 1806 isconfigured to execute commands in order of the pipeline and pass resultsfrom one command processor to the next command processor as input datato the next command processor. In one or more embodiments, eachsubsequent command processor uses the results of the prior commandprocessor. Thus, the command execution manager includes functionality tosequentially execute the pipeline in order and pass the results of theprior command processor, with the parameters to the next commandprocessor. The command execution manager 1806 may be configured toexecute multiple pipelines concurrently.

The optimizer 1808 includes functionality to optimize the pipeline usingpartial semantic information. Semantic information describes thebehavior of each command in view of corresponding parameters. Forexample, the semantics of the operations performed by the commandprocessor may relate the input to the operation with the output of theoperation. By way of another example, data semantics may be data types,whether a column or field is modified or not by execution of thecommand, whether an input variable is used to modify a resultingvariable, and other semantic information. Notably, semantic informationis distinct from syntax information that relates to form and thestructure of each instruction.

Continuing with FIG. 18, the optimizer 1808 includes functionality tochange the parameters of a command, add additional parameters to acommand, remove a command, reorder commands, and perform other actionsso as to reduce an execution time of the pipeline on a computing system.The optimizer 1808 includes such functionality using incomplete orpartial semantic information for at least one command. Incomplete orpartial semantic information is semantic information that is missing asemantic value for at least one parameter or function. For example,incomplete semantic information may have missing or partial knowledge ofthe fields required or referenced by the command, missing of partialknowledge of the fields added, modified or removed by the command,missing or incomplete knowledge of the resulting row cardinality changesintroduced by the command, or have other information that is notdefined. The incomplete or partial semantic information isindeterminable from the command. In other words, after obtaining partialsemantic information for each command of the initial pipeline, theoptimizer 1808 is configured to use the partial semantic information inorder to construct a revised pipeline that has a reduced execution timeas compared to the initial pipeline on the computing system. Morespecifically, for each missing semantic information, the optimizerincludes functionality to determine whether the missing semanticinformation may be ascertained from other information. If the missingsemantic information cannot be obtained, the optimizer includesfunctionality to determine whether the missing semantic information isrequired in order to perform an optimization, and, if not required, thento perform the optimization. Examples of optimizations include predicatepushdown and projection elimination.

As discussed above, the system of FIG. 18 may be a query evaluationpipeline. The query evaluation pipeline may be used in the systemdescribed above in FIGS. 1-17. In particular, the system of FIG. 18 maybe implemented as at least part of the search head in FIG. 2. Turning toFIG. 19, FIG. 19 shows a diagram of the system of FIG. 18 when thepipeline is a query evaluation pipeline implemented in the search head210 of FIG. 2. For simplification purposes, the execution manager is notshown in FIG. 19. The execution manager may perform the same or similaroperations as described above with reference to FIG. 18.

As described above, a query may be divided into phases (i.e., queryphases). Each query phase is a command of the query evaluation pipeline.The query phase processor 1906 may be a command processor (describedabove with respect to FIG. 18) for a query phase. For example, a queryphase processor 1906 may include a search phase processor that executesa search command to search the data stores and obtain events. In one ormore embodiments, the search phase processor may include functionalityto invoke the indexers and manage the search to obtain results. Theresults may be a portion of raw machine data that is associated with atimestamp. A query phase processor 1906 may be an aggregation phaseprocessor. The aggregation phase processor may include functionality toexecute an evaluation command. The evaluation command is a request toaggregate data to obtain processed data. For example, if the raw machinedata includes connection and disconnection requests by various computersystems to a network device, the aggregation may be the duration of timein which each computer system is connected. A query phase processor 1906may be a statistics phase processor. The statistics phase processorincludes functionality to execute a statistics command. A statisticscommand is a request to obtain a statistic about data. Although onlythree query phase processors are shown, other query phase processors mayexist without departing from the scope of the invention.

The optimizer 1908 may be the same or similar to the optimizer 1808described above with reference to FIG. 18 for query evaluationpipelines. In particular, the optimizer 1908 includes functionality toobtain an initial query evaluation pipeline, optimize the queryevaluation pipeline to generate a revised query evaluation pipeline.

Query intake 1910 is an application or user interface that includesfunctionality to receive a query evaluation pipeline. The query intakemay be the same or similar to the pipeline interface 1802 describedabove with reference to FIG. 18. The query intake 1910 may correspond toall or a portion of the user interfaces discussed above and shown inFIGS. 6A, 6B, and 7A-7D.

FIGS. 20-22 show flowcharts in accordance with one or more embodimentsof the invention. While the various steps in these flowcharts arepresented and described sequentially, one of ordinary skill willappreciate that some or all of the steps may be executed in differentorders, may be combined or omitted, and some or all of the steps may beexecuted in parallel. Furthermore, the steps may be performed activelyor passively. For example, some steps may be performed using polling orbe interrupt driven in accordance with one or more embodiments of theinvention. By way of an example, determination steps may not require aprocessor to process an instruction unless an interrupt is received tosignify that condition exists in accordance with one or more embodimentsof the invention. As another example, determination steps may beperformed by performing a test, such as checking a data value to testwhether the value is consistent with the tested condition in accordancewith one or more embodiments of the invention.

In Block 2002, an initial pipeline including a sequence of commands forexecution on a computing system is received. In one or more embodiments,the optimizer receives the initial pipeline from the pipeline interface,such as using a function call to the optimizer. When the optimizerreceives the initial pipeline, the initial pipeline may be as a Stringor a sequence of characters in one or more embodiments. For example, thepipeline may be written in SPL or another language. In one or moreembodiments, the initial pipeline may be partitioned into blockscorresponding to commands. The optimizer extracts the commands from thepipeline while maintaining the arguments of the commands.

For query evaluation pipelines, the initial pipeline may be received forperforming immediate execution and returning results. In other words, anend user may submit the query evaluation pipeline and expect a report tobe generated once based current data in the data store. As anotherexample, the initial pipeline may be received for continual executionand re-execution as new data is received by the data store. Thus, theinitial pipeline may be used for monitoring the data store, such asdiscussed above with reference to section 2.14. In other words, theinitial pipeline may be defined the analysis to perform on real data toprovide alerts of notable events.

In Block 2004, for each command in the sequence of commands, semanticinformation is obtained, where the sequence of commands includes acommand with incomplete semantic information. In some embodiments, theoptimizer includes functionality to obtain semantic informationdirectly. For example, the optimizer may have a set of rules thatrelates each command and the parameters of the command to the semanticinformation for the command and parameters. By way of another example,the optimizer may obtain semantic information from another source, suchas the corresponding command processors. The semantic information isincomplete for at least one command and may be complete for othercommands. Nevertheless, the optimizer continues to optimize the pipelineregardless of only having partial semantic information.

In Block 2006, an AST with the semantic information and a placeholderfor the incomplete semantic information is generated. The optimizerbuilds the AST according to the order of the commands in the pipeline.For example, a command that uses information from a prior command may becloser to the root of the tree than the prior commands in the pipeline.The prior commands may be listed as sources for the command. For eachcommand, the predicates of the command may be listed as parts of thecommand including the value, type of predicate, and other information.Various techniques may be used to generate an AST and embodiments arenot limited to the techniques described. For any semantic informationthat is missing, a placeholder is added to the AST. The placeholder is apredefined character or sequence of characters that indicates that thesemantic information is not available. For example, the placeholder maybe a “*”.

In Block 2008, the AST is manipulated to generate a revised AST, wherethe revised AST corresponds to a revised pipeline that reduces anexecution time on the computing system. Because the semantic informationis incomplete, the optimizer may first traverse the AST and determinewhether any missing semantic information may be determined from the AST.For example, if a first parameter has an unknown data type, but isassigned a value of a second parameter defined in a prior command, andthe second parameter has a known data type, then the first parameter isassigned the known data type. Other techniques for determining missingsemantic information may be used.

Using the AST, various types of optimization are performed. For eachtype of optimization, the optimizer makes a determination as to whethermissing semantic information is required to perform the optimization. Inother words, the optimizer includes functionality to determine whetherdifferent values of the semantic information could change the result ofexecuting the pipeline. Determining whether different values couldchange the pipeline is performed using deduction. For example, if thecommand is cardinality preserving (i.e. one input row=>one output row)and the command doesn't modify a field that is referenced by apredicate, that predicate may be moved before the command withoutaltering the final results. The reason that the predicate may be movedis because custom commands that related to a search or where command'spredicate is commutative with respect to that search or where command.Thus, a pipeline that is “ . . . |custom command|where command| . . . ”may be changed to “ . . . |where command|custom command| . . . ”, whichshould be significantly more efficient as less data is processed.

If missing semantic information is not required, then the optimizationis performed.

Different types of optimization may be performed. For example, predicatepushdown is an optimization that applies predicates as early as possiblein the pipeline, thereby avoiding searching and loading events that arenot applicable. By performing predicate pushdown, the indexers mayeliminate or reduce the number of events in the data stores that aresearched. Projection elimination reduces amount of each event obtained.In other words, the projection elimination reduces the amount of rawmachine data that is returned. Thus, if a portion of raw machine data isnot used in subsequent operations of the command pipeline, theprojection elimination removes the portion. Notably, the portion may beremoved even when the portion has incomplete semantic information basedon determining that the portion is not used. By way of another example,a command or a portion of a command may be eliminated when the commandor portion of the command is not used. For example, if the commandcalculates a value that is not used and not returned, the command may beeliminated.

By manipulating the AST by applying various optimizations even whenincomplete semantic information exists, one or more embodiments reducethe execution time of the computer system. When multiple pipelines arereceived and the data being processed is the raw machine data describedabove that is from various sources, the overall reduction in executiontime may be substantial. Further, because developers and user mayprovide new commands, complete semantic information for the new commandsmay not be known even by the developer or user. One or more embodimentsare able to operate in such an environment to reduce the execution time.

In Block 2010, the revised pipeline is executed. The revised pipelinemay be executed by rebuilding the revised pipeline from the revised ASTand then performing the execution. The revised pipeline may be executedby extracting commands from the AST and executing each command directlyrather than rebuilding the revised AST. Further, executing the revisedpipeline may include the optimizer executing the revised pipelinedirectly, the optimizer issuing a call to the command execution managerto execute the pipeline, or the optimizer performing another function tocause the pipeline to execute. In one or more embodiments, a command ofthe initial pipeline is not executed. Rather, the system may wait untilthe revised AST is generated to only execute commands in the revisedAST. Thus, actual results of executing a command are not used to performBlock 2008 in one or more embodiments.

FIG. 21 shows a flowchart for a pipeline interface to process a pipelinein accordance with one or more embodiments of the invention. FIG. 21 maybe performed prior to FIG. 20 in accordance with one or more embodimentsof the invention. In Block 2102, the pipeline interface receives thepipeline in accordance with one or more embodiments of the invention.For example, an end user may submit a data evaluation pipeline via auser interface of a local application or a web application to thepipeline interface.

In Block 2104, a determination is made whether the optimizer is enabledin accordance with one or more embodiments of the invention. Thepipeline interface may check a user selectable box that defines whetherthe optimizer is enabled. Thus, the user may select optimization or notselect optimization. If selected, then the optimizer is enabled. If notselected, the optimizer is disabled. In one or more embodiments, theoptimizer is preselected as being enabled. Various user interface and/orother application controls may dictate whether the optimizer is enabled.The above technique is only an example.

If the optimizer is disabled, the flow may proceed to Block 2106. InBlock 2106, the pipeline interface passes the pipeline to the pipelineexecution manager. For example, the pipeline interface may issue afunction call to the pipeline execution manager. The function call mayinclude the pipeline as one or more arguments. In Block 2112, thepipeline execution manager executes the pipeline in accordance with oneor more embodiments of the invention. For each command in the pipelineaccording to the order of the pipeline, the pipeline execution managersuccessively calls the command processor corresponding to the commandidentifier in the command. The call may directly or indirectly includethe parameters of the command and any results from prior execution ofthe command processor. For example, the parameters and/or results may bepassed as arguments of the call or using a shared storage.

Returning to Block 2104, if the optimizer is enabled, the flow mayproceed to Block 2110. In Block 2110, the pipeline interface passes thepipeline to the optimizer. For example, the pipeline interface may issuea function call to the optimizer. The function call may include thepipeline as one or more arguments. In Block 2114, the optimizer createsand executes a revised pipeline from the initial pipeline in accordancewith one or more embodiments of the invention. Creating and executingthe revised pipeline may be performed as discussed above in FIG. 20. Byway of another example, creating and executing the revised pipeline maybe performed as presented in FIG. 22.

In particular, FIG. 22 shows a more detailed flowchart than FIG. 20 foran optimizer to create a revised pipeline and execute the revisedpipeline. Some or all of the blocks of FIG. 22 may replace some or allof the blocks of FIG. 20 or may be performed in conjunction with theblocks of FIG. 20. Further, all embodiments of the invention are notlimited to the specific details described in FIG. 22.

Turning to FIG. 22, in Block 2202, the initial pipeline is parsed intocommands in accordance with one or more embodiments of the invention. Inparticular, a parser of the optimizer may parse the pipeline intocommands by separating out commands according to the predefineddelimiter. For each command, the parser may further extract the commandidentifier and arguments based on predefined character delimiters.

In Block 2204, for each command, the corresponding command processor isinvoked with parameters of the command and a request for semantics. Eachcommand processor may include a function that returns semanticinformation for the corresponding command of the command processor. Afunction call may be issued that includes the parameters of the command.At this stage, the command is not executed. Further, because a commandis not executed, results from a prior command are not used to determinesemantic information.

In Block 2206, a set of known semantics are received from each commandprocessor. In response to the function call of Block 2204, the commandprocessor returns the set of known semantics. For at least one commandprocessor, the set of known semantics is incomplete.

In Block 2208, an AST is generated with the set of known commands and anunknown placeholder. The AST may be generated using an AST generator,such as by issuing a call to a JSON AST generator.

In Block 2210, the AST is manipulated to generate a revised AST.Manipulating the AST may be performed as discussed above with referenceto Block 2008 of FIG. 20.

In Block 2212, a revised pipeline of revised commands is generated fromthe revised AST. The revised AST is traversed to generate the revisedpipeline. Each command is ordered and added to the revised pipeline inaccordance with the dependencies between the commands. Further, therevised parameters of the commands are added to the revised pipeline.

In Block 2214, in order of pipeline, the corresponding command processorfor each revised command is invoked with arguments of revised commandand request to execute. In other words, for each command in the revisedpipeline according to the order of the revised pipeline, the optimizersuccessively calls the command processor corresponding to the commandidentifier in the command. The call may directly or indirectly includethe parameters of the command and any results from prior execution ofthe command processor. For example, the parameters and/or results may bepassed as arguments of the call or using a shared storage. Because ofthe optimizations performed, the amount of execution time to execute therevised pipeline is decreased over the initial pipeline.

The examples shown in FIG. 23A, FIG. 23B, and described below is forexplanatory purposes only and not intended to limit the scope of theinvention.

FIG. 23A shows an example of a query pipeline in accordance with one ormore embodiments of the invention. In particular, the original query(2300) has multiple commands, each command separated from other commandsby a pipe symbol (i.e., “I”). The commands include a search command for500 search results. An evaluation command that, for each search resultindividually, multiplies fields a and b, then stores the multipliedresult into field x of the search result. The evaluation command thendivides x by c and puts the result in field y of the search result. Thenext command is a where command that filters out any search result wherea is not greater than 10 and x is not greater than 100. The fieldscommand returns only fields x, a, and b of the search results.

The query intake receives the original query and sends the originalquery to the optimizer. The optimizer parses the query into phrases(2302), which are comma separated and on separate lines as shown in FIG.23A. The optimizer then issues separate calls to the query phaseprocessors (2304). For example, the optimizer issues a separate call tothe search processor for the search command, to the evaluation processorfor the evaluation command, to the where processor for the wherecommand, and to the fields processor for the fields command. Inresponse, each command processor responds with syntax information forthe command. Notably, the syntax information does not includeinformation from executing the command, but rather only syntax that canbe gathered from the command itself.

The optimizer than builds the following AST using the obtained syntaxinformation. To aid in readability for visual explanatory purposes only,the AST shown below is in an outline tree view. In the optimizer, theparenthesis and other delimiting characters are sufficient to indicatethe structure of the tree. As shown in the AST below, any missinginformation that is not known is marked with a “*” to indicate that theinformation is not known.

  1. {    a. “pipeline”: “streaming”,    b. “keep_column_order”: false,   c. “sources”: [{        i. “pipeline”: “streaming”,       ii.“predicate”: {         1. “args”: [           a. {             i.“args”: [               1. {                 a. “type”: “field”,                b. “value”: “a”               2. },               3. {                a. “type”: “number”,                 b. “value”: 10              4. }              ii. ],             iii. “type”:“function”,             iv. “value”: “>”           b. },           c. {            i. “args”: [               1. {                 a. “type”:“field”,                 b. “value”: “x”               2. },              3. {                 a. “type”: “number”,                b. “value”: 100               4. }              ii. ],            iii. “type”: “function”,             iv. “value”: “>”          d. }         2. ],         3. “type”: “function”,         4.“value”: “AND”       iii. },       iv. “sources”: [{         1.“pipeline”: “streaming”,         2. “assignments”: [           a. {             i. “expression”: “a*b”,              ii. “field”: “x”,            iii. “value”: {               1. “args”: [                a. {                    i. “type”: “field”,                  ii. “value”: “a”                 b. },                c. {                    i. “type”: “field”,                  ii. “value”: “b”                 d. }               2.],               3. “type”: “function”,               4. “value”: “*”            iv. }           b. },           c. {              i.“expression”: “x/c”,              ii. “field”: “y”,             iii.“value”: {               1. “args”: [                 a. {                   i. “type”: “field”,                   ii. “value”:“x”                 b. },                 c. {                    i.“type”: “field”,                   ii. “value”: “c”                 d. }              2. ],               3. “type”: “function”,              4. “value”: “/”             iv. }           d. }        3. ],         4. “sources”: [{           a. “pipeline”:“streaming”,           b. “predicate”: {              i. “args”: [{              1. “type”: “term”,               2. “value”: “500”             ii. }],             iii. “type”: “function”,            iv. “value”: “AND”           c. },           d.“fields_and_properties”: [              i. {               1.“referenced”: true,               2. “name”: “_raw”              ii. },            iii. {               1. “name”: “*”,               2.“modified”: true             iv. }           e. ],           f. “type”:“SP_STREAM”,           g. “command”: “search”         5. }],         6.“fields_and_properties”: [           a. {              i. “referenced”:true,             ii. “name”: “a”           b. },           c. {             i. “referenced”: true,             ii. “name”: “b”          d. },           e. {              i. “referenced”: true,            ii. “name”: “c”           f. },           g. {             i. “referenced”: true,              ii. “name”: “x”,            iii. “modified”: true           h. },           i. {             i. “name”: “y”,             ii. “modified”: true          j. }         7. ],         8. “type”: “SP_STREAM”,         9.“command”: “eval”        v. }],       vi. “fields_and_properties”: [        1. {           a. “referenced”: true,           b. “name”: “a”        2. },         3. {           a. “referenced”: true,           b.“name”: “x”         4. }        vii. ],       viii. “type”: “SP_STREAM”,       ix. “command”: “where”     d. }],     e. “keep_underscored”:true,     f. “fields_and_properties”: [        i. {         1.“filterable”: true,         2. “referenced”: true,         3. “name”:“a”        ii. },       iii. {         1. “filterable”: true,         2.“referenced”: true,         3. “name”: “b”       iv. },        v. {        1. “filterable”: true,         2. “referenced”: true,         3.“name”: “x”        vi. },       vii. {         1. “removed”: true,        2. “name”: “*”       viii. },        ix. {         1.“filterable”: true,         2. “name”: “_*”        x. }     g. ],     h.“type”: “SP_STREAM”,     i. “remove_attributes”: false,     j.“field_list”: [        i. “x”,        ii. “a”,       iii. “b”     k. ],    l. “command”: “fields”,     m. “table”: false 2. }

Continuing with the example, based on the analysis of the above AST, theoptimizer performs predicate pushdown. To perform predicate pushdown,the optimizer visits nodes (e.g., shown as separate lines) in the ASTlooking for predicates it can push down. While visiting the nodes, theoptimizer finds the where command and notices that the optimizer canpush half the where predicate (shown in bold in the AST above) down tothe root search (shown in bold in the AST below). In the AST, pushingdown mean pushing the nodes as child nodes of other nodes.

   1. {    a. “pipeline”: “streaming”,    b. “keep_column_order”: false,   c. “sources”: [{        i. “pipeline”: “streaming”,       ii.“predicate”: {          1. “args”: [{             a. “args”: [                i. {                   1. “type”: “field”,                  2. “value”: “x”                 ii. },               iii. {                   1. “type”: “number”,                  2. “value”: 100                iv. }             b. ],            c. “type”: “function”,             d. “value”: “>”         2. }],          3. “type”: “function”,          4. “value”:“AND”       iii. },       iv. “sources”: [{          1. “pipeline”:“streaming”,          2. “assignments”: [             a. {                i. “expression”: “a*b”,                 ii. “field”:“x”,                iii. “value”: {                   1. “args”: [                     a. {                          i. “type”: “field”,                        ii. “value”: “a”                      b. },                     c. {                          i. “type”: “field”,                        ii. “value”: “b”                      d. }                  2. ],                   3. “type”: “function”,                  4. “value”: “*”                iv. }             b. },            c. {                 i. “expression”: “x/c”,                ii. “field”: “y”,                iii. “value”: {                  1. “args”: [                      a. {                         i. “type”: “field”,                         ii.“value”: “x”                      b. },                      c. {                         i. “type”: “field”,                         ii.“value”: “c”                      d. }                   2. ],                  3. “type”: “function”,                   4. “value”:“/”                iv. }             d. }          3. ],          4.“sources”: [{             a. “pipeline”: “streaming”,             b.“predicate”: {                i. “args”: [                   1. {                     a. “type”: “term”,                      b. “value”:“500”                   2. },                   3. {                     a. “args”: [                           i. {                          ii. “type”: “field”,                         iii. “value”: “a”                          iv.},                           v. {                          vi. “type”:“string”,                          vii. “value”: “10”                        viii. }                      b. ],                     c. “is_numeric”: false,                      d.“type”: “function”,                      e. “value”: “>”,                     f. “is_indexed”: false                   4. }                ii. ],                iii. “type”: “function”,               iv. “value”: “AND”             c. },             d.“fields_and_properties”: [                 i. {                   1.“referenced”: true,                   2. “name”: “a”                 ii.},                iii. {                   1. “referenced”: true,                  2. “name”: “_raw”                iv. },                v. {                   1. “name”: “*”,                  2. “modified”: true                vi. }            e. ],             f. “type”: “SP_STREAM”,             g.“command”: “search”          5. }],          6. “fields_and_properties”:[             a. {                 i. “referenced”: true,               ii. “name”: “a”             b. },             c. {                i. “referenced”: true,                ii. “name”: “b”            d. },             e. {                 i. “referenced”:true,                ii. “name”: “c”             f. },             g. {                i. “referenced”: true,                 ii. “name”: “x”,               iii. “modified”: true             h. },             i. {                i. “name”: “y”,                ii. “modified”: true            j. }          7. ],          8. “type”: “SP_STREAM”,         9. “command”: “eval”         v. }],        vi.“fields_and_properties”: [{          1. “referenced”: true,          2.“name”: “x”        vii. }],       viii. “type”: “SP_STREAM”,        ix.“command”: “where”    d. }],    e. “keep_underscored”: true,    f.“fields_and_properties”: [        i. {          1. “filterable”: true,         2. “referenced”: true,          3. “name”: “a”        ii. },      iii. {          1. “filterable”: true,          2. “referenced”:true,          3. “name”: “b”       iv. },        v. {          1.“filterable”: true,          2. “referenced”: true,          3. “name”:“x”        vi. },       vii. {          1. “removed”: true,          2.“name”: “_*”       viii. },        ix. {          1. “filterable”: true,         2. “name”: “_*”       x. }    g. ],    h. “type”: “SP_STREAM”,   i. “remove_attributes”: false,    j. “field list”: [        i. “x”,       ii. “a”,       iii. “b”    k. ],    l. “command”: “fields”,    m.“table”: false 2. }

As a result of the predicate pushdown, the underlying original query hasbeen optimized from:

search 500|eval x=a*b, y=x/c|where a>10 AND x>100|fields x, a, b

to:

search 500 a>10|eval x=a*b, y=x/c|where x>100|fields x, a, b

The predicate pushdown is possible because the evaluation commandadvertises via the AST that the a field is unmodified by that command,hence a filter before and a filter after are equivalent.

Continuing with the example, the optimizer performs projectionelimination by visiting the AST looking for unnecessary calculations.The optimizer identifies the y fields as not being needed. This is shownin that the fields_and_properties for the commands that the fieldscommand does not reference Y. Thus, the projection elimination removes yfrom the AST as shown below (shown in bold with the comment “//removedsection”):

   1. {    a. “pipeline”: “streaming”,    b. “keep_column_order”: false,   c. “sources”: [{        i. “pipeline”: “streaming”,       ii.“predicate”: {          1. “args”: [{             a. “args”: {                i. {                   1. “type”: “field”,                  2. “value”: “x”                 ii. },               iii. {                   1. “type”: “number”,                  2. “value”: 100                iv. }             b. ],            c. “type”: “function”,             d. “value”: “>”         2. }],          3. “type”: “function”,          4. “value”:“AND”       iii. },       iv. “sources”: [{          1. “pipeline”:“streaming”,          2. “assignments”: [             a. {                i. “expression”: “a*b”,                 ii. “field”:“x”,                iii. “value”: {                   1. “args”: [                     a. {                          i. “type”: “field”,                        ii. “value”: “a”                      b. },                     c. {                          i. “type”: “field”,                        ii. “value”: “b”                      d. }                  2. ],                   3. “type”: “function”,                  4. “value”: “*”                iv. }             b. }            c. //REMOVED SECTION          3. ],          4. “sources”:[{             a. “pipeline”: “streaming”,             b. “predicate”: {               i. “args”: [                   1. {                     a. “type”: “term”,                      b. “value”:“500”                   2. },                   3. {                     a. “args”: [                           i. {                         ii. “type”: “field”,                         iii. “value”: “a”                          iv.},                           v. {                          vi. “type”:“string”,                          vii. “value”: “10”                        viii. }                      b. ],                     c. “is_numeric”: false,                      d.“type”: “function”,                      e. “value”: “>”,                     f. “is_indexed”: false                   4. }                ii. },                iii. “type”: “function”,               iv. “value”: “AND”             c. },             d.“fields_and_properties”: [                 i. {                   1.“referenced”: true,                   2. “name”: “a”                 ii.},                iii. {                   1. “referenced”: true,                  2. “name”: “_raw”                iv. },                v. {                   1. “name”: “*”,                  2. “modified”: true                vi. }            e. ],             f. “type”: “SP_STREAM”,             g.“command”: “search”          5. }],          6. “fields_and_properties”:[             a. {                 i. “referenced”: true,               ii. “name”: “a”             b. },             c. {                i. “referenced”: true,                ii. “name”: “b”            d. },             e. {                 i. “referenced”:true,                ii. “name”: “c”             f. },             g. {                i. “referenced”: true,                 ii. “name”: “x”,               iii. “modified”: true             h. },             i. {                i. “name”: “y”,                ii. “modified”: true            j. }          7. ],          8. “type”: “SP_STREAM”,         9. “command”: “eval”         v. }],        vi.“fields_and_properties”: [{          1. “referenced”: true,          2.“name”: “x”        vii. }],       viii. “type”: “SP_STREAM”,        ix.“command”: “where”    d. }],    e. “keep_underscored”: true,    f.“fields_and_properties”: [           i. {          1. “filterable”:true,          2. “referenced”: true,          3. “name”: “a”         ii. },         iii. {          1. “filterable”: true,         2. “referenced”: true,          3. “name”: “b”         iv. },         v. {          1. “filterable”: true,          2. “referenced”:true,          3. “name”: “x”         vi. },        vii. {          1.“removed”: true,          2. “name”: “*”       viii. },        ix. {         1. “filterable”: true,          2. “name”: “_*”        x. }   g. ],    h. “type”: “SP_STREAM”,    i. “remove_attributes”: false,   j. “field_list”: [        i. “x”,        ii. “a”,       iii. “b”   k. ],    l. “command”: “fields”,    m. “table”: false 2. }

In the above example, the resulting optimized query is:

search 500 a>10|eval x=a*b|where x>100|fields x, a, b

With the predicate pushdown, the number of search results are greatlyreduced, thereby reducing the number of search results that areprocessed. With the projection elimination, fewer calculations areperformed on each returned search result. As shown, even where onlypartial information is known, the optimizer causes the computing systemto operate more efficiently.

In the example of FIG. 23B, consider the scenario in which the commandssubmitted in the original query (2320) are identical to the commandssubmitted in 23A with the exception that rather than call a nativeevaluation command, a custom evaluation command (i.e., “myeval”) iscalled. As with the example of 23A, the optimizer parses the query intophrases (2322) and calls the corresponding query phrase processor foreach phase (2324). The result is the following AST (the bolded sectionbelow shows the modification from example 23A).

   1. {       a. “pipeline”: “streaming”,       b. “keep_column_order”:false,       c. “sources”: [{           i. “pipeline”: “streaming”,         ii. “predicate”: {             1. “args”: [                a. {                  i. “args”: [                      1. {                        a. “type”: “field”,                         b.“value”: “a”                      2. },                      3. {                        a. “type”: “number”,                         b.“value”: 10                      4. }                    ii. ],                  iii. “type”: “function”,                   iv.“value”: “>”                b. },                c. {                  i. “args”: [                      1. {                        a. “type”: “field”,                         b.“value”: “x”                      2. },                      3. {                        a. “type”: “number”,                         b.“value”: 100                      4. }                    ii. ],                  iii. “type”: “function”,                   iv.“value”: “>”                d. }             2. ],             3.“type”: “function”,             4. “value”: “AND”          iii. },         iv. “sources”: [{             1. “pipeline”: “streaming”,            2. “assignments”: [                a. {                 i.“expression”: “a*b”,                 ii. “field”: “x”,               iii. “value”: {                   1. “args”: [                     a. {                          i. “type”: “field”,                        ii. “value”: “a”                      b. },                     c. {                          i. “type”: “field”,                        ii. “value”: “b”                      d. }                  2. ],                   3. “type”: “function”,                  4. “value”: “/”                iv. }             b. },            c. {                 i. “expression”: “x/c”,                ii. “field”: “y”,                iii. “value”: {                  1. “args”: [                      a. {                         i. “type”: “field”,                         ii.“value”: “x”                      b. },                      c. {                         i. “type”: “field”,                         ii.“value”: “c”                      d. }                   2. ],                  3. “type”: “function”,                   4. “value”:“/”                iv. }             d. }          3. ],          4.“sources”: [{             a. “pipeline”: “streaming”,             b.“predicate”: {                 i. “args”: [{                   1.“type”: “term”,                   2. “value”: “500”                 ii.}],                iii. “type”: “function”,                iv. “value”:“AND”             c. },             d. “fields_and_properties”: [                i. {                   1. “referenced”: true,                  2. “name”: “_raw”                 ii. },               iii. {                   1. “name”: “*”,                  2. “modified”: true                iv. }            e. ],             f. “type”: “SP_STREAM”,             g.“command”: “search”          5. }],          6. “fields_and_properties”:{             a. {                 i. “modified”: true,               ii. “name”: “X”             b. },             c. {                i. “modified”: true,                ii. “name”: “Y”            d. },             e. {                 i. “name”: “*”               ii. “referenced”: true,             f. },          7. ],         8. “type”: “SP_STREAM”,          9. “command”: “myeval”        v. }],        vi. “fields_and_properties”: [          1. {            a. “referenced”: true,             b. “name”: “a”         2. },          3. {             a. “referenced”: true,            b. “name”: “x”          4. }        vii. ],       viii.“type”: “SP_STREAM”,        ix. “command”: “where”    d. }],    e.“keep_underscored”: true,    f. “fields_and_properties”: [          i. {         1. “filterable”: true,          2. “referenced”: true,         3. “name”: “a”         ii. },        iii. {          1.“filterable”: true,          2. “referenced”: true,          3. “name”:“b”         iv. },         v. {          1. “filterable”: true,         2. “referenced”: true,          3. “name”: “x”        vi. },       vii. {          1. “removed”: true,          2. “name”: “*”      viii. },        ix. {          1. “filterable”: true,          2.“name”: “_*”        x. }    g. ],    h. “type”: “SP_STREAM”,    i.“remove_attributes”: false,    j. “field_list”: [        i. “x”,       ii. “a”,       iii. “b”    k. ],    1. “command”: “fields”,    m.“table”: false 2. }

In the example of 23B, the optimizer may perform predicate pushdown forsimilar reasons as the example of 23A. However, because the customevaluation command does not identify the fields that are modified,projection elimination cannot be performed. In many cases, the amount ofinformation is dependent on the custom command author's ability toprovide semantic information. Nevertheless, even with the incompleteinformation, the query pipeline can be optimized from:

search 500|myeval x=a*b, y=x/c|where a>10 AND x>100|fields x, a, b

to:

search 500 a>10|myeval x=a*b, y=x/c|where x>100|fields x, a, b

Notably, even though the optimization reduces the number of searchresults (i.e., to only those search results having a field a greaterthan 10) processed by the myeval command processor in the above querypipeline, the above optimization is still capable of being performed.Thus, as shown, even with the incomplete semantic information, one ormore embodiments reduce the execution time on the computing system.

4.0 Hardware

The various components of the figures may be a computing system orimplemented on a computing system. For example, the operations of thedata stores, indexers, search heads, host device(s), client devices,data intake and query systems, data sources, external resources, and/orany other component shown and/or described above may be performed by acomputing system. A computing system may include any combination ofmobile, desktop, server, router, switch, embedded device, or other typesof hardware. For example, as shown in FIG. 5.1, the computing system mayinclude one or more computer processors, non-persistent storage (e.g.,volatile memory, such as random access memory (RAM), cache memory),persistent storage (e.g., a hard disk, an optical drive such as acompact disk (CD) drive or digital versatile disk (DVD) drive, a flashmemory, etc.), a communication interface (e.g., Bluetooth interface,infrared interface, network interface, optical interface, etc.), andnumerous other elements and functionalities. The computer processor(s)may be an integrated circuit for processing instructions. For example,the computer processor(s) may be one or more cores or micro-cores of aprocessor. The computing system may also include one or more inputdevices, such as a touchscreen, keyboard, mouse, microphone, touchpad,electronic pen, or any other type of input device.

The computing system may be connected to or be a part of a network. Forexample, the network may include multiple nodes. Each node maycorrespond to a computing system, such as the computing system, or agroup of nodes combined may correspond to the computing system. By wayof an example, embodiments of the invention may be implemented on a nodeof a distributed system that is connected to other nodes. By way ofanother example, embodiments of the invention may be implemented on adistributed computing system having multiple nodes, where each portionof the invention may be located on a different node within thedistributed computing system. Further, one or more elements of theaforementioned computing system may be located at a remote location andconnected to the other elements over a network.

The node may correspond to a blade in a server chassis that is connectedto other nodes via a backplane. By way of another example, the node maycorrespond to a server in a data center. By way of another example, thenode may correspond to a computer processor or micro-core of a computerprocessor with shared memory and/or resources.

The nodes in the network may be configured to provide services for aclient device. For example, the nodes may be part of a cloud computingsystem. The nodes may include functionality to receive requests from theclient device and transmit responses to the client device. The clientdevice may be a computing system. Further, the client device may includeand/or perform all or a portion of one or more embodiments of theinvention.

Software instructions in the form of computer readable program code toperform embodiments of the invention may be stored, in whole or in part,temporarily or permanently, on a non-transitory computer readable mediumsuch as a CD, DVD, storage device, a diskette, a tape, flash memory,physical memory, or any other computer readable storage medium.Specifically, the software instructions may correspond to computerreadable program code that, when executed by a processor(s), isconfigured to perform one or more embodiments of the invention.

While the above figures show various configurations of components, otherconfigurations may be used without departing from the scope of theinvention. For example, various components may be combined to create asingle component. As another example, the functionality performed by asingle component may be performed by two or more components.

While the invention has been described with respect to a limited numberof embodiments, those skilled in the art, having benefit of thisdisclosure, will appreciate that other embodiments can be devised whichdo not depart from the scope of the invention as disclosed herein.Accordingly, the scope of the invention should be limited only by theattached claims.

What is claimed is:
 1. A method comprising: receiving, by at least onecomputing system, a query comprising an initial pipeline comprising asequence of commands for execution on a computing system, wherein thesequence of commands comprises a search command to search for data in adata store, and an evaluation command to process at least a portion ofthe data obtained from the data store using the search command, whereinthe data comprises values for at least one field, and wherein theevaluation command comprises a predicate in the initial pipeline; priorto executing the search command of the sequence of commands, obtaining,for each command in the sequence of commands and by the computingsystem, semantic information, wherein the sequence of commands comprisesa command with a missing semantic value; generating, by the computingsystem, an abstract semantic tree (AST) with the semantic informationand a placeholder for the missing semantic value, wherein theplaceholder is a predefined sequence of at least one character thatindicates the missing semantic value is missing, wherein generating theAST comprises: adding the predicate of the evaluation command as a firstchild of the evaluation command in the AST, and adding the searchcommand as a second child of the evaluation command based on the searchcommand being a data source for the evaluation command; generating, bythe computing system, a revised AST from the AST, wherein generating therevised AST comprises moving the predicate of the evaluation commandfrom the first child of the evaluation command to a first child of thesearch command, wherein the predicate is moved based on determining thatthe missing semantic value is not required to move the predicate;generating, from the revised AST, a revised pipeline comprising thesearch command and the evaluation command, and wherein the searchcommand comprises the predicate based on moving the predicate in the ASTto generate the revised AST; and executing, by the computing system, therevised pipeline.
 2. The method of claim 1, further comprising: parsingthe initial pipeline into the sequence of commands.
 3. The method ofclaim 1, further comprising: invoking, for each command in the sequenceof commands and prior to executing the search command, a correspondingcommand processor with a request for the semantic information; andreceiving, for each command in the sequence of commands, semanticinformation comprising known semantics of the command from thecorresponding command processor.
 4. The method of claim 1, whereinexecuting the revised pipeline comprises: invoking, in order specifiedby the revised pipeline, a command processor for each correspondingcommand in the revised pipeline with a request execute the correspondingcommand.
 5. The method of claim 1, further comprising: receiving, by apipeline interface, the initial pipeline; determining, by the pipelineinterface, that an optimizer is enabled; and passing, by the pipelineinterface, the initial pipeline to the optimizer to create the revisedpipeline.
 6. The method of claim 1, wherein manipulating the ASTcomprises: performing projection elimination on the AST to generate therevised AST.
 7. The method of claim 1, wherein generating the revisedAST is performed before any command of the initial pipeline is executed.8. The method of claim 1, wherein the initial pipeline further comprisesa statistics command.
 9. The method of claim 1, further comprising:distributing a revised query in the revised pipeline to a plurality ofindexers to obtain a plurality of events, the revised query furtherlimiting a number of events returned from an original query in theinitial pipeline based on the evaluation command in the initialpipeline; executing the evaluation command in the revised pipeline onthe plurality of events to obtain at least one result; and executing astatistics command in the revised pipeline to obtain a statistic aboutthe at least one result.
 10. The method of claim 1, further comprising:distributing a revised query in the revised pipeline to a plurality ofindexers to obtain a plurality of events, the revised query furtherlimiting a number of events returned from an original query in theinitial pipeline based on the evaluation command in the initialpipeline, wherein each event in the plurality of events correspond to aportion of raw machine data associated with a timestamp; executing theevaluation command in the revised pipeline on the plurality of events toobtain at least one result; and executing a statistics command in therevised pipeline to obtain a statistic about the at least one result.11. The method of claim 1, wherein execution of the revised pipeline isbased on a late-binding schema.
 12. The method of claim 1, furthercomprising: searching raw machine data using a revised query in therevised pipeline to obtain a plurality of events, the revised queryfurther limiting a number of events returned from an original query inthe initial pipeline based on the evaluation command in the initialpipeline.
 13. A system comprising: a computing system for executing arevised pipeline; a computer processor for executing instructions thatcause the computer processor to perform operations comprising: receivinga query comprising an initial pipeline comprising a sequence of commandsfor execution on the computing system, wherein the sequence of commandscomprises a search command to search for data in a data store, and anevaluation command to process at least a portion of the data obtainedfrom the data store using the search command, wherein the data comprisesvalues for at least one field, and wherein the evaluation commandcomprises a predicate in the initial pipeline; prior to executing thesearch command of the sequence of commands, obtaining, for each commandin the sequence of commands, semantic information, wherein the sequenceof commands comprises a command with a missing semantic value;generating an abstract semantic tree (AST) with the semantic informationand a placeholder for the missing semantic value, wherein theplaceholder is a predefined sequence of at least one character thatindicates the missing semantic value is missing, wherein generating theAST comprises: adding the predicate of the evaluation command as a firstchild of the evaluation command in the AST, and adding the searchcommand as a second child of the evaluation command based on the searchcommand being a data source for the evaluation command; generating arevised AST from the AST, wherein generating the revised AST comprisesmoving the predicate of the evaluation command from the first child ofthe evaluation command to a first child of the search command, whereinthe predicate is moved based on determining that the missing semanticvalue is not required to move the predicate; generating, from therevised AST, the revised pipeline comprising the search command and theevaluation command, and wherein the search command comprises thepredicate based on moving the predicate in the AST to generate therevised AST; and executing the revised pipeline.
 14. The system of claim13, wherein the operations further comprise: invoking, for each commandin the sequence of commands and prior to executing the search command, acorresponding command processor with a request for the semanticinformation; and receiving, for each command in the sequence ofcommands, semantic information comprising known semantics of the commandfrom the corresponding command processor.
 15. The system of claim 13,wherein manipulating the AST comprises: performing projectionelimination on the AST to generate the revised AST.
 16. The system ofclaim 13, wherein generating the revised AST is performed before anycommand of the initial pipeline is executed.
 17. The system of claim 13,wherein the operations further comprise: distributing a revised query inthe revised pipeline to a plurality of indexers to obtain a plurality ofevents, the revised query further limiting a number of events returnedfrom an original query in the initial pipeline based on the evaluationcommand in the initial pipeline, wherein each event in the plurality ofevents correspond to a portion of raw machine data associated with atimestamp; executing the evaluation command in the revised pipeline onthe plurality of events to obtain at least one result; and executing astatistics command in the revised pipeline to obtain a statistic aboutthe at least one result.
 18. The system of claim 13, wherein theoperations further comprise: searching raw machine data using a revisedquery in the revised pipeline to obtain a plurality of events, therevised query further limiting a number of events returned from anoriginal query in the initial pipeline based on the evaluation commandin the initial pipeline.
 19. A non-transitory computer-readable storagemedium storing computer-readable program code which, when executed byone or more processors, cause the one or more processors to performoperations, comprising: receiving a query comprising an initial pipelinecomprising a sequence of commands for execution on a computing system,wherein the sequence of commands comprises a search command to searchfor data in a data store, and an evaluation command to process at leasta portion of the data obtained from the data store using the searchcommand, wherein the data comprises values for at least one field, andwherein the evaluation command comprises a predicate in the initialpipeline; prior to executing the search command of the sequence ofcommands, obtaining, for each command in the sequence of commands,semantic information, wherein the sequence of commands comprises acommand with a missing semantic value; generating an abstract semantictree (AST) with the semantic information and a placeholder for themissing semantic value, wherein the placeholder is a predefined sequenceof at least one character that indicates the missing semantic value ismissing, wherein generating the AST comprises: adding the predicate ofthe evaluation command as a first child of the evaluation command in theAST, and adding the search command as a second child of the evaluationcommand based on the search command being a data source for theevaluation command; generating a revised AST from the AST, whereingenerating the revised AST comprises moving the predicate of theevaluation command from the first child of the evaluation command to afirst child of the search command, and wherein the predicate is movedbased on determining that the missing semantic value is not required tomove the predicate; generating, from the revised AST, a revised pipelinecomprising the search command and the evaluation command, and whereinthe search command comprises the predicate based on moving the predicatein the AST to generate the revised AST; and executing the revisedpipeline.
 20. The non-transitory computer-readable storage medium ofclaim 19, wherein the operations further comprise: invoking, for eachcommand in the sequence of commands and prior to executing the searchcommand, a corresponding command processor with a request for thesemantic information; and receiving, for each command in the sequence ofcommands, semantic information comprising known semantics of the commandfrom the corresponding command processor.
 21. The non-transitorycomputer-readable storage medium of claim 19, wherein manipulating theAST comprises: performing projection elimination on the AST to generatethe revised AST.
 22. The non-transitory computer-readable storage mediumof claim 19, wherein generating the revised AST is performed before anycommand of the initial pipeline is executed.
 23. The non-transitorycomputer-readable storage medium of claim 19, wherein the operationsfurther comprise: distributing a revised query in the revised pipelineto a plurality of indexers to obtain a plurality of events, the revisedquery further limiting a number of events returned from an originalquery in the initial pipeline based on the evaluation command in theinitial pipeline, wherein each event in the plurality of eventscorrespond to a portion of raw machine data associated with a timestamp;executing the evaluation command in the revised pipeline on theplurality of events to obtain at least one result; and executing astatistics command in the revised pipeline to obtain a statistic aboutthe at least one result.
 24. The non-transitory computer: readablestorage medium of claim 19, wherein the operations further comprise:searching raw machine data using a revised query in the revised pipelineto obtain a plurality of events, the revised query further limiting anumber of events returned from an original query in the initial pipelinebased on the evaluation command in the initial pipeline.